A weight limiting mechanism for AGV balance fork truck

Abstract

The utility model discloses a kind of weight limiting mechanisms for AGV balance fork truck, it is related to balanced fork truck technical field, including fork truck plate, adjusting groove weight limiting frame, two moving rods can drive guiding frame to move in adjusting groove, the use position of two weight limiting frames is realized to adjust, guiding frame is limited to position work to moving wheel, the load-bearing article on the load cell on the limiting side plate and limiting side rod of weight limiting frame top carries out limiting protection work, load cell can weigh load and limit its weight work, T type moving block can slide in the inner side surface of guide rail, realize using two heat dissipation net board to first round corner special-shaped positioning frame, second round corner special-shaped positioning frame reinforcing limit, to limit reinforcing using first round corner special-shaped positioning frame, second round corner special-shaped positioning frame to the use of load cell, connecting barrel between adjacent first round corner special-shaped positioning frame, second round corner special-shaped positioning frame is realized when load cell is protected buffering effect to it using limiting spring when being impacted.

Description

Technical Field

[0001] This utility model relates to the field of counterbalanced forklift technology, and in particular to a weight limiting mechanism for AGV counterbalanced forklifts. Background Technology

[0002] Counterbalance forklifts are an essential component of smart factories and smart workshops, and are now widely used in various industries such as electronics, automotive, chemical, pharmaceutical, logistics, metallurgy, and assembly. They replace manual machinery in loading, handling, and unloading tasks, thus automating workshop logistics. AGV, short for Automated Guided Vehicle, refers to a transport forklift equipped with electromagnetic or optical automatic guidance devices, capable of traveling along a prescribed guide path, and possessing safety protection and various transfer functions. AGV counterbalance forklifts do not require a driver; under the control of the forklift's central control mechanism, they can move in any direction and lift and unload goods, offering flexibility and convenience.

[0003] A patent with publication number CN218909775U discloses a weight-limiting mechanism for an AGV counterbalance forklift. This patent includes a carriage body, mounting frame, load-bearing frame, support arm, support beam, pallet body, arc-shaped groove, mast assembly, lifting cylinder, guide sleeve, guide shaft, elastic element, locking pad, and limit switch. When the load exceeds the maximum load capacity, the pallet body descends, compressing the compression spring. This triggers the limit switch, and the forklift's central control mechanism, upon receiving the limit switch signal, cuts off the hydraulic circuit of the lifting cylinder, preventing the forklift's center of gravity from becoming unstable due to the rising load, thus preventing the forklift from tipping over and improving the safety of forklift operation. The arc-shaped groove allows the loaded coiled material to be embedded within it. During forklift lifting and movement, the arc-shaped groove provides good restraint for the coiled material, ensuring stable loading and preventing the safety hazards caused by the coiled material rolling over. However, this patent still has the following problems: However, in actual operation, issues such as overloading, center of gravity shift, and dynamic impacts can lead to forklift imbalance, tipping over, equipment damage, and even safety accidents. Traditional AGV forklifts mostly lack real-time, accurate, and dynamic weight monitoring and limit protection, making them particularly prone to tipping over when handling special goods such as rolled materials and irregularly shaped parts due to an unstable center of gravity.

[0004] To address the above issues, a weight-limiting mechanism for AGV counterbalanced forklifts needs to be designed to overcome these problems. Utility Model Content

[0005] The main purpose of this utility model is to provide a weight limiting mechanism for AGV counterbalance forklifts, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A weight-limiting mechanism for an AGV (Automated Guided Vehicle) balance forklift includes a forklift platform and an adjusting groove weight-limiting frame. Guide rails are installed at both ends of the inner side of the weight-limiting frame. T-shaped moving blocks are connected to the inner sides of both guide rails. One end of each T-shaped moving block is connected to a second rounded corner positioning block via a universal joint. A heat dissipation mesh plate is connected to the end of each second rounded corner positioning block away from the universal joint. A universal joint is connected to the end of each T-shaped moving block near the second rounded corner positioning block. A second fixing plate is connected to the side of each T-shaped moving block away from the guide rails. A first rounded corner irregular positioning frame and a second rounded corner irregular positioning frame are respectively connected to the end of the second fixing plate away from the T-shaped moving blocks. A connecting cylinder is connected between adjacent first and second rounded corner irregular positioning frames. A limit spring is connected to the end of each connecting cylinder away from the first and second rounded corner irregular positioning frames.

[0007] As a preferred embodiment of this utility model, a movable rod is connected to the inner side of the adjusting groove, a guide frame is connected between two adjacent movable rods, a movable wheel is connected to the inner side of the guide frame, a first fixing plate is installed on the top of the guide frame, and a fixing rod is installed on the top of the first fixing plate.

[0008] As a preferred embodiment of this utility model, a weighing sensor is provided in the middle of the inner side of the weight-limiting frame, and limit side plates are fixedly installed at both ends of the top of the weight-limiting frame, with limit side rods welded to the top of the limit side plates.

[0009] As a preferred embodiment of this utility model, the T-shaped moving block is slidably connected to the inner side of the guide rail, the T-shaped moving block is rotatably connected to the second rounded corner positioning block through the universal joint, and the second rounded corner positioning block is threadedly fixedly connected to the two heat dissipation mesh plates.

[0010] As a preferred embodiment of this utility model, the T-shaped moving block is fixedly connected to the second fixed plate, and the second fixed plate is fixedly connected to the first rounded corner irregular positioning frame and the second rounded corner irregular positioning frame.

[0011] As a preferred embodiment of this utility model, the first rounded corner irregular positioning frame and the second rounded corner irregular positioning frame are rotatably connected to the connecting cylinder, the connecting cylinder is fixedly connected to the limiting spring, and one side of the first rounded corner irregular positioning frame and the second rounded corner irregular positioning frame are in contact with the weighing sensor.

[0012] In a preferred embodiment of this utility model, the movable rod is slidably connected to the inner side of the adjusting groove, the movable rod is rotatably connected to the guide frame, the guide frame is fixedly connected to the first fixed plate, the first fixed plate is rotatably connected to the fixed rod, and the top of the fixed rod is rotatably connected to the bottom of the weight-limiting frame.

[0013] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: This AGV balance forklift uses a weight-limiting mechanism. Two movable rods move the guide frame within an adjustment slot, allowing for adjustment of the two weight-limiting frames' positions. The guide frame limits the movement of the wheels. Limiting side plates and rods on top of the weight-limiting frames provide protection for the load on the load cells. The load cells weigh the load and limit its weight. T-shaped moving blocks slide on the inner side of the guide rail. Two heat dissipation plates reinforce and limit the first and second rounded-corner irregular-shaped positioning frames, thus reinforcing and limiting the load cells. A connecting cylinder between adjacent first and second rounded-corner irregular-shaped positioning frames uses a limiting spring to provide cushioning and protection for the load cells in the event of an impact. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of structure A of this utility model; Figure 3 This is a schematic diagram of the movable wheel installation structure of this utility model; Figure 4 This is a schematic diagram of the installation structure of the weighing sensor of this utility model; Figure 5 This is a schematic diagram of the installation structure of the first rounded corner irregular positioning frame and the second rounded corner irregular positioning frame of this utility model.

[0015] In the diagram: 1. Forklift platform; 2. Adjustment groove; 3. Moving rod; 4. Guide frame; 5. First fixed plate; 6. Fixed rod; 7. Weight limit frame; 8. Moving wheel; 9. Limiting side plate; 10. Limiting side rod; 11. Weighing sensor; 12. Guide rail; 13. T-shaped moving block; 14. First rounded corner positioning block; 15. Second rounded corner positioning block; 16. Universal joint; 17. Second fixed plate; 18. First rounded corner irregular positioning frame; 19. Second rounded corner irregular positioning frame; 20. Connecting cylinder; 21. Limiting spring; 22. Heat dissipation mesh plate. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0017] like Figures 1-5As shown, a weight-limiting mechanism for an AGV (Automated Guided Vehicle) balance forklift includes a forklift platform 1, an adjustment groove 2, and a weight-limiting frame 7. Guide rails 12 are mounted on both ends of the inner side of the weight-limiting frame 7. T-shaped moving blocks 13 are connected to the inner sides of both guide rails 12. One end of each T-shaped moving block 13 is connected to a second rounded corner positioning block 15 via a universal joint 16. A heat dissipation mesh 22 is connected to the end of the second rounded corner positioning block 15 away from the universal joint 16. A universal joint is connected to the end of the T-shaped moving block 13 closest to the second rounded corner positioning block 15. Section 16, the side of the two T-shaped moving blocks 13 away from the guide rail 12 is connected to a second fixing plate 17. The end of the second fixing plate 17 away from the T-shaped moving blocks 13 is respectively connected to a first rounded corner irregular positioning frame 18 and a second rounded corner irregular positioning frame 19. A connecting cylinder 20 is connected between adjacent first rounded corner irregular positioning frames 18 and second rounded corner irregular positioning frames 19. The end of the connecting cylinder 20 away from the first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 is connected to a limit spring 21. A weighing sensor 11 is installed in the middle of the inner side of the weight-limiting frame 7. Limiting side plates 9 are fixedly installed at both ends of the top of the weight-limiting frame 7. Limiting side rods 10 are welded to the top of the limiting side plates 9. T-shaped moving blocks 13 are slidably connected to the inner side of the guide rail 12. T-shaped moving blocks 13 are rotatably connected to the second rounded corner positioning block 15 through a universal joint 16. The second rounded corner positioning block 15 is threadedly fixedly connected to two heat dissipation mesh plates 22. T-shaped moving blocks 13 are fixedly connected to the second fixed plate 17. The second fixed plate 17 is fixedly connected to the first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19. The first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 are rotatably connected to the connecting cylinder 20. The connecting cylinder 20 is fixedly connected to the limiting spring 21. One side of the first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 is in contact with the weighing sensor 11. Specifically, in this embodiment, limit side plates 9 are vertically welded to both ends of the top of each weight-limiting frame 7. A horizontally extending limit side rod 10 is further welded to the top of the limit side plate 9. The limit side plate 9 and the limit side rod 10 together form an L-shaped protective structure. When goods are placed on the weighing sensor 11, this structure can effectively physically block the goods from the side and end, preventing slippage or overturning during AGV operation, acceleration, deceleration, or turning. The AGV forklift smoothly places the goods onto the weighing sensors 11 of the two weight-limiting frames 7. The weight of the goods is accurately captured by the sensors and converted into an electrical signal, which is transmitted to the AGV's main control system. Simultaneously, the limit side plate 9 and the limit side rod 10 are in close contact with the side of the goods, providing immediate protection. The control system compares the real-time weight with a preset safety threshold. If the weight exceeds the threshold, it immediately executes safety commands such as prohibiting lifting and issuing an alarm. On the inner side of each weight-limiting frame 7, on both sides of the load cell 11, two guide rails 12 are symmetrically installed. On the inner side of each guide rail 12, a T-shaped moving block 13 is slidably connected. The T-shaped structure of the T-shaped moving block 13 matches the T-shaped groove of the guide rail 12, ensuring that it can only slide along the length of the guide rail and will not come off. The two T-shaped moving blocks 13 are connected as a whole by a second fixing plate 17. On the side of the second fixing plate 17 facing the load cell 11, a first rounded corner irregular positioning frame 18 and a second rounded corner irregular positioning frame 19 are fixedly installed. The rounded corners and irregular shapes of these two positioning frames are designed to better fit the side contour of the load cell 11, achieving large-area, stable contact and support. On the other side, each T-shaped moving block 13 is connected to a second rounded corner positioning block 15 via a universal joint 16. The design of the universal joint 16 allows for a slight angular deviation between the T-shaped moving block 13 and the second rounded corner positioning block 15, which helps to eliminate assembly stress and accommodate minor twisting. Two heat dissipation mesh plates 22 are threaded onto each second rounded corner positioning block 15. These two heat dissipation mesh plates 22 are located on the upper and lower sides of the T-shaped moving block 13, respectively. They not only provide additional support for the entire assembly, but more importantly, the mesh structure they form facilitates airflow and dissipates heat from the weighing sensor 11 during operation. A connecting cylinder 20 is connected between adjacent first rounded corner irregular positioning frames 18 and second rounded corner irregular positioning frames 19 via a rotating shaft. A limiting spring 21 is fixedly connected to the other end of each connecting cylinder 20. The other end of the limiting spring 21 is fixed to the inner wall of the weight-limiting frame 7. Under normal weighing conditions, the first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 are in close contact with the side of the weighing sensor 11, applying a preload to prevent it from undergoing slight displacement under load, thus ensuring the stability and accuracy of weighing. At this time, the limit spring 21 is in a pre-compressed state. When the goods are not placed stably or the forklift is bumped, causing the weighing sensor 11 to be subjected to a lateral impact, the impact force will be transmitted to the first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 to push the connecting cylinder 20, further compressing the limit spring 21. The limit spring 21 absorbs the impact energy through elastic deformation, thereby protecting the weighing sensor 11 from damage. After the impact, the spring returns to its original position, pushing the entire buffer assembly back to its original position.

[0018] The inner side of the adjusting groove 2 is connected to a moving rod 3, and a guide frame 4 is connected between two adjacent moving rods 3. The inner side of the guide frame 4 is connected to a moving wheel 8, and a first fixing plate 5 is installed on the top of the guide frame 4. A fixing rod 6 is installed on the top of the first fixing plate 5. The movable rod 3 is slidably connected to the inner side of the adjusting groove 2, the movable rod 3 is rotatably connected to the guide frame 4, the guide frame 4 is fixedly connected to the first fixed plate 5, the first fixed plate 5 is rotatably connected to the fixed rod 6, and the top of the fixed rod 6 is rotatably connected to the bottom of the weight limit frame 7. Specifically, in this embodiment, two parallel adjustment slots 2 are symmetrically provided on the upper surface of the forklift plate 1 along the width direction of the forks. A moving rod 3 is slidably connected in each adjustment slot 2. The upper ends of the two moving rods 3 are rotatably connected to a guide frame 4 by a pin or bolt, so that the guide frame 4 can move linearly along the adjustment slot 2 with the moving rods 3, and can also swing slightly at an angle to adapt to installation errors. Several moving wheels 8 are installed inside the guide frame 4 through bearings. These moving wheels 8 contact the upper surface of the forklift plate 1, and play a supporting role and reduce friction, making the entire adjustment process easier and smoother. A first fixing plate 5 is welded or fixed to the top of the guide frame 4 by bolts. A fixing rod 6 is connected to the top of the first fixing plate 5 by a rotating shaft. The other end of the fixing rod 6 is rotatably connected to the bottom of the weight limit frame 7. A weighing sensor 11 is fixedly installed in the middle of the inner side of the two weight limit frames 7 by bolts or a special mounting seat. The weighing sensor 11 is preferably a high-precision shear beam type or column type sensor, and its top surface is the cargo bearing surface. When the width needs to be adjusted, the operator pushes one of the weight-limiting frames 7 inward or outward. The weight-limiting frame 7 drives the first fixed plate 5 and the guide frame 4 to move through the fixed rod 6. The guide frame 4 then slides in the adjustment groove 2 through the moving rod 3. Since all connections are rotational or sliding connections, there is no jamming in the whole process. The moving wheel 8 ensures the smoothness of the movement. After the adjustment is in place, the position can be locked by setting a set bolt (not shown in the figure) at the connection between the T-shaped moving block 13 and the guide rail 12.

[0019] It should be noted that this utility model is a weight limiting mechanism for AGV balance forklifts. In use, the operator manually or through a small motor drives the weight limiting frame 7. Since the T-shaped moving block 13 at the bottom of the weight limiting frame 7 is embedded in the guide rail 12, the weight limiting frame 7 can only slide smoothly laterally along the track of the guide rail 12. When the weight limiting frame 7 moves, it will drive the entire sensor protection and reinforcement assembly at its bottom to move together. At the same time, the guide frame 4, which is connected to the weight limiting frame 7 through the fixed rod 6 and the first fixed plate 5, will also be driven in the adjustment groove 2. The moving rod 3 slides in the adjustment groove 2, providing guidance and support for the entire movement process, ensuring that the adjustment process is linear and stable. After adjusting to the appropriate position, the T-shaped moving block 13 is locked on the guide rail 12 by the locking device to prevent displacement during operation. The AGV forklift places the goods into the load-bearing area above the two weight limit frames 7. The weight of the goods is directly applied to the weighing sensor 11. At the same time, the limit side plate 9 and the limit side rod 10 physically block the goods from the sides and rear to prevent the goods from sliding or tipping over during the start, stop, turn or lift of the forklift, thus playing a preliminary stabilizing role. The weighing sensor 11 converts the pressure it receives into an electrical signal and transmits it to the AGV's main control system in real time. If the weight is within the safe range, the AGV will normally perform subsequent operations such as handling and lifting. If the weight exceeds the safe threshold, the control system will immediately trigger the weight limit protection program. If the goods are tilted and impacted during placement, or if the forklift is bumped during operation, the impact force will be transmitted to the load cell 11 first. The load cell 11 will be subjected to a lateral or longitudinal thrust, which will be immediately transmitted to the first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 that are close to its side. These two positioning frames are connected to the limit spring 21 through the connecting cylinder 20. When subjected to impact, the positioning frame will slightly compress the limiting spring 21. The limiting spring 21 is compressed and produces elastic deformation, absorbing the instantaneous impact kinetic energy and converting it into the potential energy of the spring. This greatly reduces the impact force transmitted to the weighing sensor 11 body, preventing it from being damaged due to overload or hard impact. After the impact, the spring returns to its original shape, and the positioning frame is pushed back to its original position through the connecting cylinder 20. Throughout the entire working process, the heat dissipation mesh plate 22 connected to the positioning frame is always in working condition. The weighing sensor 11 generates heat when working. The heat dissipation mesh plate 22 increases the air circulation area, which helps to dissipate heat quickly and ensures the measurement accuracy and stability of the sensor under long-term, high-intensity work. The design of the universal joint 16 allows for slight angle self-adaptation between the connecting parts when adjusting or subjected to small torque, avoiding stress concentration or jamming of rigid connections under complex stress. Compared to existing technologies and comparative documents, where the load-bearing frame is fixed in position and cannot be adjusted according to the width or center of gravity of the goods, this invention addresses the issue of unstable placement and center of gravity shift when handling goods of different sizes. This severely limits the operational compatibility of the AGV and reduces handling efficiency. The present invention features an adjustment groove 2 on the forklift platform 1 and a position adjustment assembly consisting of a moving rod 3, a guide frame 4, moving wheels 8, and a fixed rod 6. When handling goods of different widths, the operator can easily push the weight-limiting frame 7. The moving rod 3 slides smoothly within the adjustment groove 2, while the moving wheels 8 at the bottom of the guide frame 4 effectively reduce friction, ensuring a smooth and effortless adjustment process. Through this structure, the present invention achieves stepless adjustment of the distance between the two weight-limiting frames 7. This allows the AGV forklift to adaptively carry goods of varying widths, from standard pallets to irregularly shaped parts, ensuring that the goods are always stably supported in the optimal position. Compared to existing technologies, this solution significantly expands the operating range of a single AGV forklift, reduces operational interruptions or equipment replacements caused by mismatched cargo specifications, and thus significantly improves the compatibility and operational efficiency of the overall logistics system. Most comparative solutions only focus on weight monitoring and lack physical constraints on the cargo itself. When the AGV starts, stops, turns, or traverses uneven surfaces at high speeds, cargo is prone to sliding, tilting, or even falling, leading to safety accidents and cargo loss. This invention integrates or welds L-shaped limiting side plates 9 and limiting side rods 10 onto the top of each weight-limiting frame 7. When cargo is placed on the weighing sensor 11, these two sets of protective structures form effective physical barriers from the sides and ends of the cargo. The first rounded corner irregular positioning frame 18 and the second rounded corner irregular positioning frame 19 are tightly attached to the side of the sensor, providing rigid support; while the limiting spring 21, connected to them via the connecting cylinder 20, provides elastic buffering. When the sensor is subjected to a lateral impact, the impact force is transmitted by the positioning frame to the limiting spring 21, which absorbs energy through compression deformation, protecting the sensor body.

[0020] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A weight limiting mechanism for AGV balance forklifts, comprising a forklift plate (1), a weight limiting frame (7) and an adjusting groove (2), characterized in that: The inner sides of the weight-limiting frame (7) are each equipped with a guide rail (12). T-shaped moving blocks (13) are connected to the inner sides of both guide rails (12). One end of each T-shaped moving block (13) is connected to a second rounded corner positioning block (15) via a universal joint (16). A heat dissipation mesh plate (22) is connected to the end of the second rounded corner positioning block (15) away from the universal joint (16). A universal joint (16) is connected to the end of each T-shaped moving block (13) near the second rounded corner positioning block (15). The two T-shaped moving blocks (13) are further apart from each other. One side of the guide rail (12) is connected to a second fixing plate (17). The end of the second fixing plate (17) away from the T-shaped moving block (13) is connected to a first rounded corner irregular positioning frame (18) and a second rounded corner irregular positioning frame (19). A connecting cylinder (20) is connected between adjacent first rounded corner irregular positioning frames (18) and second rounded corner irregular positioning frames (19). A limit spring (21) is connected to the end of the connecting cylinder (20) away from the first rounded corner irregular positioning frame (18) and second rounded corner irregular positioning frame (19).

2. The weight limiting mechanism for the AGV balanced forklift according to claim 1, characterized in that: The inner side of the adjustment groove (2) is connected to a moving rod (3), and a guide frame (4) is connected between two adjacent moving rods (3). The inner side of the guide frame (4) is connected to a moving wheel (8). A first fixing plate (5) is installed on the top of the guide frame (4), and a fixing rod (6) is installed on the top of the first fixing plate (5).

3. The weight limiting mechanism for the AGV balanced forklift according to claim 1, characterized in that: A weighing sensor (11) is provided in the middle of the inner side of the weight limit frame (7). Limiting side plates (9) are fixedly installed at both ends of the top of the weight limit frame (7). Limiting side rods (10) are welded to the top of the limiting side plates (9).

4. The weight-limiting mechanism for an AGV counterbalance forklift according to claim 1, characterized in that: The T-shaped moving block (13) is slidably connected to the inner side of the guide rail (12). The T-shaped moving block (13) is rotatably connected to the second rounded corner positioning block (15) through the universal joint (16). The second rounded corner positioning block (15) is threadedly fixedly connected to the two heat dissipation mesh plates (22).

5. The weight limiting mechanism for AGV balance forklift according to claim 1, characterized in that: The T-shaped moving block (13) is fixedly connected to the second fixed plate (17), and the second fixed plate (17) is fixedly connected to the first rounded corner irregular positioning frame (18) and the second rounded corner irregular positioning frame (19).

6. The weight limiting mechanism for AGV balance forklift according to claim 1, characterized in that: The first rounded corner irregular positioning frame (18) and the second rounded corner irregular positioning frame (19) are rotatably connected to the connecting cylinder (20), and the connecting cylinder (20) is fixedly connected to the limiting spring (21). The first rounded corner irregular positioning frame (18) and the second rounded corner irregular positioning frame (19) are in contact with the weighing sensor (11) on one side and the other side on the other side.

7. The weight limiting mechanism for AGV balance forklift according to claim 2, characterized in that: The moving rod (3) is slidably connected to the inner side of the adjusting groove (2), the moving rod (3) is rotatably connected to the guide frame (4), the guide frame (4) is fixedly connected to the first fixing plate (5), the first fixing plate (5) is rotatably connected to the fixing rod (6), and the top of the fixing rod (6) is rotatably connected to the bottom of the weight limit frame (7).

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