A chain-driven large telescopic ratio constant force lifting platform and its operation method

Abstract

The present invention relates to a chain-driven large telescopic ratio constant-force lifting platform and its operation method. The lifting platform includes a base, a scissor mechanism, a lifting platform, a chain lifting mechanism and a control system. The chain lifting mechanism includes at least one sprocket mounted on the base. The sprocket meshes with a chain, and the top of the chain is connected to the bottom of the lifting platform through a rotating pair. The chain includes alternately connected inner links and outer links, and a limiting mechanism. The limiting mechanism includes a first limiting mechanism and a second limiting mechanism that respectively limit the opposite rotation directions of adjacent links, and bidirectionally lock the chain during the vertical lifting movement. Through the limiting effect of the limiting mechanism and the detection and control of the control system, the present invention automatically realizes the stable self-locking and simple unlocking of the chain, intelligently matches the driving power and speed of the motor, ensures the constant-force lifting of the chain in the vertical direction, provides a constant-force lifting platform with a large telescopic ratio, effectively simplifies the equipment, reduces energy consumption and improves the lifting efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of conveying robots, and particularly relates to a chain-driven large-stroke ratio constant-force lifting platform. Background Art

[0002] A lifting platform is a hoisting machine for vertically transporting people or objects. It mainly includes a workbench, a base, a cross-type lifting mechanism, and an electric drive component. The electric drive component drives the workbench to lift through the cross-type lifting mechanism, so as to lift an object to different heights. It is widely used in fields such as logistics, warehouses, and automated production lines. Generally, the electric drive component uses a motor to drive a lead screw or a hydraulic rod, and the rotation of the lead screw or the telescopic movement of the hydraulic rod drives the scissor arms in the cross-type lifting mechanism to move, thereby realizing the lifting movement of the platform.

[0003] However, due to the structural limitations of the current traditional scissor-type lifting platform, the driving force required by the motor is not a constant force during the lifting process of the platform, which brings certain difficulties to motor control. For the lead screw scissor mechanism, during the movement, when the lifting platform is at the lowest position, the scissor arms are almost in a completely horizontal state. At this time, the system is at a dead point of motion. Driving the scissor-type lifting platform to rise at the dead point position requires the motor to provide a large driving force, which poses higher requirements on the power and size of the driving motor. For the hydraulic rod scissor-type lifting mechanism, due to its own structural limitations, its stroke ratio is relatively small.

[0004] Therefore, those skilled in the art have tried to adopt a chain drive method to reduce energy consumption and expand the stroke ratio of the platform. Patent application CN107651616A discloses a height-adjustable chain jacking device, which includes: a jacking platform, a telescopic guiding device, a servo motor, a speed reducer, a chain, a motor mounting plate, and a bottom support mounting component; the motor mounting plate is mounted on the bottom support mounting component; the telescopic guiding device is fixed on the bottom support mounting component; the jacking platform is fixed on the telescopic guiding device; the servo motor and the speed reducer are cooperatively mounted and then fixed on the motor mounting plate; a sprocket is mounted on the output shaft of the speed reducer; the chain is wound and mounted on the motor mounting plate, and the chain is cooperatively mounted with the sprocket, and the chain extends to the jacking platform. Compared with the cylinder-controlled lifting, this invention is more practical and convenient, saves space, can control its lifting speed and stopping position, can be jacked up and lowered as much as possible according to the chain length, and can better cooperate with other automation equipment or production lines.

[0005] Patent CN103552948B discloses a scissor-type lifting platform for skateboards, including a sliding fork arm, a fixed fork arm, a support plate and a base, wherein the sliding fork arm and the fixed fork arm connect the support plate and the base, and further include a rigid chain, a driving sprocket and a driving motor, wherein one end of the rigid chain is fixed on the support plate, the driving motor is fixed on the base, and its output shaft is connected to the driving sprocket, the rigid chain bypasses the driving sprocket, and the pin shaft of the rigid chain meshing surface meshes with the teeth of the driving sprocket. After the rigid chain meshes with the driving sprocket, its extension direction changes, and the rigid chain between the driving sprocket and the support plate is in an erected state. The rigid chain can also be stored in a curled state, saving installation space and reducing the requirements for installation space. The length of the rigid chain can be adjusted as needed, and the lifting height of the lifting platform will not be limited.

[0006] However, in the chain-driven lifting device mentioned above, the limit structure of the transmission chain during the lifting force process is single, and the chain locking stability is still insufficient. When affected by external shaking or vibration, the rigidity provided by the transmission chain only by locking in one direction is easy to collapse due to the rotation of the non-locking direction between the chain links, which leads to the transfer of the device force, causing damage to the device components and safety risks. In addition, due to differences in the weight of the load, lifting speed, etc., the energy consumption requirements of the device operation are not exactly the same. A unified operating standard will not be conducive to energy saving. However, the existing technologies have not paid attention to the role of intelligent control systems in promoting device operation safety and energy saving.

[0007] How to utilize the advantages of chain drive to provide a stable, safe, energy-saving and efficient large telescopic ratio constant force lifting platform is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a chain-driven constant force lifting platform with a large telescopic ratio, which fully utilizes the advantages of chain drive, avoids the disadvantage of excessive driving force required at the dead point position, and realizes constant force lifting with a large telescopic ratio; provides a stable and safe chain lifting mechanism by setting a two-way limit structure; and the setting of an intelligent control system automatically matches the appropriate driving force for lifting requirements, thereby reducing energy consumption and saving costs.

[0009] Specifically, the present invention provides a chain-driven large telescopic ratio constant force lifting platform, including a base, a scissor mechanism, a lifting platform, a chain lifting mechanism and a control system;

[0010] The scissor mechanism is connected between the base and the lifting platform through a rotating pair and a moving pair respectively;

[0011] The chain lifting mechanism comprises at least one sprocket wheel and a driving motor thereof mounted on a base, wherein the driving motor is electrically connected to the control system; the sprocket wheel is meshed with a chain, and the top of the chain is connected to the bottom of the lifting platform through a rotating pair;

[0012] The chain includes alternately connected inner link plates and outer link plates, and a limiting mechanism; the limiting mechanism includes a first limiting mechanism and a second limiting mechanism that respectively limit the opposite rotation directions of adjacent link plates, and the chain is locked bidirectionally during the lifting movement in the vertical direction.

[0013] Through the setting of the limiting mechanism, it is ensured that the adjacent inner link plates and outer link plates of the chain rotate relative to each other during the lifting process, so that the chain shows a rigid transmission and support effect during the lifting process, and maintains the movement in the vertical direction without being affected by the outside world. Regarding the specific positions of the first limiting mechanism and the second limiting mechanism, they can both be arranged on the inner link plates or both on the outer link plates. Preferably, the first limiting mechanism is arranged on the inner link plates and the second limiting mechanism is arranged on the outer link plates, so as to simplify the structure of a single link plate and facilitate production and replacement.

[0014] The driving motor can be installed on the base or assembled separately outside the base. It can cooperate with a speed reducer, and the sprocket is installed on the output shaft of the speed reducer. When multiple sprockets are provided, the same motor can be used for linkage drive to ensure lifting synchronization; or independent driving motors can be used to drive each sprocket separately, and the lifting synchronization is monitored and controlled through a control system, and individual driving conditions can be adjusted in real time as needed.

[0015] Furthermore, the scissor mechanism includes a first fork arm and a second fork arm. The upper end of the first fork arm is connected to the lifting platform through a rotating pair, and the upper end of the second fork arm is connected to the lifting platform through a moving pair; the lower end of the first fork arm is connected to the base through a moving pair, and the lower end of the second fork arm is connected to the base through a rotating pair.

[0016] Preferably, the middle parts of the first fork arm and the second fork arm are connected through a rotating pair; the moving pair includes a slider and a slide rail connected in a sliding manner. The slide rails are respectively fixed on the base and the lifting platform. The lower end of the first fork arm is connected to a first slider to connect to the base, and the upper end of the second fork arm is connected to a second slider to connect to the lifting platform. Preferably, the scissor mechanism includes at least two groups of scissor mechanisms. More preferably, the scissor mechanisms are arranged in parallel between the lifting platform and the base.

[0017] The purpose of using the scissor mechanism in the present invention is not to use it as a power system, but mainly to utilize the relatively stable telescopic performance of the scissor mechanism to provide stable guiding guarantee for the lifting process of the lifting platform.

[0018] Further, the first limiting mechanism includes a plurality of limiting baffles integrally formed with the inner link or the outer link. The limiting baffles are located on the side of the inner link or the outer link facing away from the sprocket, restricting the rotation of adjacent links in the first direction. Preferably, the first limiting mechanism is arranged on the inner link, that is, the first limiting mechanism includes a plurality of limiting baffles integrally formed with the inner link. The limiting baffles are located on the side of the inner link facing away from the sprocket, restricting the rotation of the adjacent outer link in the first direction. More preferably, 4 limiting baffles are provided, which are respectively located in the tangential direction of the curved surfaces at the four corners on the outer side of the inner link and are parallel to the central connection line of the two connecting shafts of the inner link. The limiting baffles have sufficient width and length and can extend to the outer side wall of the adjacent outer link to stop and limit the adjacent outer link, preventing it from rotating excessively in the first direction.

[0019] Further, the inner link and the outer link are rotatably connected by a connecting shaft, and the inner link is fixed to the connecting shaft; the second limiting mechanism includes a ratchet wheel, a ratchet pawl and an elastic member. The ratchet wheel is fixed on the connecting shaft, the ratchet pawl is rotatably fixed on the outer link, and one end of the elastic member is fixed on the outer link and the other end abuts against the ratchet pawl; the separation and abutment of the ratchet pawl and the ratchet wheel are realized by the abutment and separation of the sprocket teeth and the ratchet pawl, so as to unlock or limit the rotation of the outer link in the second direction; the second direction is opposite to the first direction.

[0020] Through the cooperation of the internal components of the second limiting mechanism and its external cooperation with the first limiting mechanism and the sprocket, during the process of the chain winding around the sprocket and meshing with it, the sprocket teeth abut against the ratchet pawl and compress the elastic member, causing the ratchet pawl to separate from the ratchet wheel, and the outer link rotates in the second direction, making the chain show flexibility; in the lifting section and the storage section of the chain, that is, when not in contact and meshing with the sprocket, the ratchet pawl abuts against the ratchet wheel under the elastic restoring force of the elastic member, restricting the rotation of the outer link in the second direction, and the central connection lines of the connecting shafts of the chain are basically in a straight line, making the chain show rigidity. Optionally, when the lifting platform is at the bottom or in the low position, the horizontal section of the chain that has not passed through the sprocket is stored in the base cavity; in order to save storage space, a storage sprocket can be arranged in the bottom cavity. Based on the similar principle of the sprocket that provides driving force mentioned above, the storage sprocket cooperates with the limiting mechanism of the chain, making the chain show flexibility and realizing bending storage.

[0021] The elastic member can select common elastic components in the art. As long as the elastic member is convenient to operate, occupies little space and can provide sufficient elastic restoring force, it can be selected, such as springs, leaf springs, etc. The control system mainly includes a main controller (such as STM32F407 MCU) and corresponding information collection modules (such as STM32F103 MCU), calculation modules and other common components.

[0022] Further, the sprocket is a double-row sprocket, one row of teeth of which meshes with the chain, and the other row of teeth cooperates with the pawl. Selecting a double-row sprocket divides the two rows of teeth on both sides. One row of teeth is used for meshing and driving with the chain, and the other row of teeth cooperates with the pawl to achieve unlocking or limiting. The number and position of the two rows of teeth on both sides correspond to each other, but the tooth profile can be slightly changed as needed to facilitate the full play of their respective functions. The advantage of using a double-row sprocket is also that the position of the second limiting mechanism including the ratchet, the pawl and the elastic member is more flexible. When using an ordinary single-row sprocket, a single row of teeth needs to simultaneously mesh with the chain and cooperate with the pawl. The second limiting mechanism needs to be arranged on the inner side of the outer chain link, which has relatively high requirements for the structural cooperation of the chain link, and has a high failure rate and a large maintenance difficulty. When using a double-row sprocket, the second limiting mechanism of the outer chain link can be arranged on the outer side surface of the outer chain link, so that the inner side and the outer side of the outer chain link respectively play the functions of meshing and limiting, with a clear structure, a larger layout space, and more convenient replacement and maintenance.

[0023] Further, the chain lifting mechanism includes at least two double-row sprockets; on the side of the chain facing away from the double-row sprockets, there is a vertical guide plate fixed on the upper surface of the base, and the height H of the vertical guide plate and the radius R of the double-row sprocket satisfy: R ≤ H ≤ 2R. According to the load-bearing requirements and force conditions of the lifting platform, a number of double-row sprockets are symmetrically arranged on the base. For example, two double-row sprockets are symmetrically arranged in the length direction of the bottom plate, which is beneficial to sharing the lifting power and providing a more stable and balanced lifting action. In order to improve the fitting degree between the chain and the sprocket, prevent the two from separating during the meshing process, and reduce the shaking at the position where the chain is about to leave the sprocket during lifting, the vertical guide plate can play a role in protecting and guiding the chain, which is beneficial to the stable lifting movement of the chain in the vertical direction.

[0024] Further, a load platform is provided above the lifting platform, and a number of load sensors connected to the control system by signals are arranged between the load platform and the lifting platform. The control system obtains the total weight of the load platform and its load by collecting the detection information of the load sensors, so as to determine the output power of the drive motor.

[0025] Further, load sensors are arranged at the four corners of the lifting platform, and the load platform is supported and connected through the load sensors. Through the above settings, when the object to be lifted is placed on the load platform, the control system immediately receives the load information. If the total weight exceeds the threshold, the control system will send a prompt message; optionally, according to the load information fed back by the load sensors at the four corners, it is judged whether the placement position of the load is in the safe area. If the load difference at the four corners exceeds the set threshold, it means that the placement position of the object needs to be adjusted, otherwise during the lifting process, there will be uneven force, resulting in equipment damage and safety risks. On the other hand, according to the total weight of the load platform and its load, and the required lifting speed, the total output power and rotation speed required by the drive motor are calculated to prepare for lifting.

[0026] Preferably, between the total weight M of the load platform and its load, the set lifting speed v, the total output power P of the driving motor, and the sprocket speed n, the following formula is satisfied:

[0027]

[0028] M = M1 + M2 + M3 + M4 (2);

[0029]

[0030] Wherein, M0 is the weight of the lifting platform; v is the set lifting speed; f is the transmission efficiency, and f is 0.8 - 0.9; M1 - M4 are the weight values detected by four load sensors; z is the number of teeth of the sprocket; d is the chain pitch, in mm; n is the sprocket speed, in r / min; t is the lifting time, α is the elastic modulus of the first fork arm or the second fork arm, L is the length of the first fork arm or the second fork arm, and T is the moment of inertia of the first fork arm or the second fork arm. The transmission efficiency is an empirical value obtained through multiple experiments considering corresponding losses such as the self-weight of the chain, system friction, and heat energy loss. The system can select and correct according to conditions such as the total load weight and lifting speed.

[0031] When the lifting speed is preset, the control system can match the appropriate total output power of the motor for the operation of the lifting platform according to the load information detected by the load sensor, which is not only beneficial to providing stable drive, enhancing work safety, but also can effectively save energy. When the lifting speed needs to be adjusted, by adjusting the motor speed, the sprocket speed can be quickly changed, and at the same time, the control system will also match the corresponding total output power of the motor to make the switching process transition smoothly and reduce operation risks.

[0032] In addition to setting load sensors, a pose sensor signal-connected to the control system is further set to detect the pose information of the lifting platform. For example, the levelness of the platform, vibration frequency, etc. The pose sensor can be set on the upper surface or the lower surface of the lifting platform, or at other positions according to needs. Although most lifting risks can be avoided through the detection values of the above load sensors, by adding a pose sensor, the lifting situation can be displayed more quickly and intuitively. Especially when the lifting object is a moving object, the pose sensor can quickly feedback to the control system according to the pose change of the lifting platform to adjust the driving motor speed, and warn of lifting risks and issue prompt information or alarms when necessary.

[0033] In addition, for the convenience of use, on the basis of not affecting the lifting stability, moving components can also be set on the base, such as moving tracks, or lockable pulleys can be set at the bottom of the base. The above moving components are signal-connected to the control system to achieve intelligent moving and positioning control.

[0034] Correspondingly, the present invention further provides an operation method for the above chain-driven large telescopic ratio constant force lifting platform, including the following steps:

[0035] Place the object to be lifted on the lifting platform;

[0036] The driving motor drives the sprocket to rotate, conveys the chain engaged with the sprocket upward, restricts the relative rotation of adjacent inner and outer chain links of the chain through the limiting mechanism, ensures the lifting movement of the chain in the vertical direction, and realizes the lifting of the object.

[0037] Preferably, the specific operation method further includes that when the chain contacts the sprocket, the row of teeth of the sprocket meshes with the chain, and at the same time, the pawl is pushed to separate from the ratchet, the outer chain link can rotate, and the chain link is in an unlocked state; when the chain leaves the sprocket, the pawl separates from the sprocket, and the restoring force of the elastic member presses the pawl against the ratchet, and the chain link is locked in the second direction; with the cooperation of the limiting baffle, the outer chain link cannot rotate in the first direction either, and the first direction and the second direction are opposite, and the chain is conveyed in a double-direction self-locking manner.

[0038] More preferably, a double-row sprocket is used. When the chain contacts the double-row sprocket, one row of teeth of the double-row sprocket meshes with the chain, and the other row of teeth pushes the pawl to separate from the ratchet, the outer chain link can rotate, and the chain link is in an unlocked state; when the chain leaves the double-row sprocket, the pawl separates from the double-row sprocket, and the restoring force of the elastic member presses the pawl against the ratchet, and the chain link is locked in the second direction; with the cooperation of the limiting baffle structure, the outer chain link cannot rotate in the first direction either, and the chain is conveyed in a double-direction self-locking manner.

[0039] The chain-driven large telescopic ratio constant force lifting platform and its operation method provided by the present invention have at least the following beneficial effects:

[0040] 1. In the present invention, a chain lifting structure is adopted to realize the lifting of the platform. Compared with the traditional scissor drive structure, the driving force of the present invention is a constant force, and the control system design is simple and reliable; compared with the traditional screw scissor structure, the present invention has no dead point position in motion, and the requirements for the power and size of the motor are relatively low; compared with the traditional hydraulic rod scissor structure, the present invention can realize a larger telescopic ratio of lifting.

[0041] 2. By adopting a limiting mechanism, especially the limiting baffle of the first limiting mechanism on the inner chain link and the second limiting mechanism including a ratchet, a pawl and an elastic member on the outer chain link, the rigid-flexible switching of the chain is realized in cooperation with the teeth of the sprocket row, so that the chain is locked in both directions during the lifting process, ensuring the stable and safe progress of the lifting process. And the chain can be completely accommodated inside the base together with the sprocket without occupying extra space.

[0042] 3. The setting of the intelligent control system significantly improves the operation safety and energy conservation. The present invention uses a load sensor to detect the carrying weight, which can automatically adjust the output power of the driving motor and reduce the system power consumption; further, a pose sensor is used to detect the pose of the lifting platform to monitor and maintain the stability and safety of the platform in real time. Description of the Drawings

[0043] Figure 1 Front view schematic diagram of the lifting platform of the present invention;

[0044] Figure 2 Schematic diagram of the chain link locking state when the chain sprocket is not engaged;

[0045] Figure 3 Schematic diagram of the chain link unlocking state when the chain sprocket is engaged;

[0046] Figure 4 Schematic diagram of the control system of the present invention;

[0047] Figure 5 Schematic diagram of the process flow of the control system of the present invention;

[0048] Reference numerals: 1. Base, 11. Vertical guide plate, 2. Chain lifting mechanism, 21. Chain, 211. Outer chain link, 2111. Pawl, 2122. Ratchet wheel, 2112. Spring, 212. Inner chain link, 2121. Limit baffle, 22. Double-row sprocket, 221. Row of teeth, 3. Scissor mechanism, 30. First fork arm, 31. Second fork arm, 32. Slide block, 4. Lifting platform, 41. Pose sensor, 42. Load sensor, 5. Load platform. Detailed Description of the Invention

[0049] The terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0050] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed" and other terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] It should also be noted that the terms "include", "comprise", "have" or any other variants thereof are intended to cover non-exclusive inclusion, such that a commodity or device comprising a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such commodity or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the commodity or device comprising said element.

[0052] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The specific embodiments are the preferred embodiments of the present invention, not the only embodiments, and do not necessarily limit the protection scope of the present invention.

[0053] As Figure 1 shown, the large telescopic ratio constant force lifting platform driven by a chain of the present invention includes a base 1, a chain lifting mechanism 2, a scissor mechanism 3, a lifting platform 4 and a control system.

[0054] The chain lifting mechanism 2 includes a chain 21, a double-row sprocket 22 and its driving motor. The chain 21 meshes with one row of teeth of the double-row sprocket 22. The bottom of the double-row sprocket 22 is connected to the base 1 through a rotating pair. The top of the chain 21 is connected to the bottom of the lifting platform 4 through a rotating pair. The bottom end of the double-row sprocket 22 and the chain 21 can be received inside the base 1. The chain lifting mechanism includes two double-row sprockets 22, which are symmetrically distributed at both ends in the length direction of the base 1. On the side of the chain 21 facing away from the double-row sprocket 22, there is a vertical guide plate 11 fixed on the upper surface of the base 1. The height H of the vertical guide plate 11 and the radius R of the double-row sprocket 22 satisfy: R ≤ H ≤ 2R.

[0055] Two groups of scissor mechanisms 3 are arranged in parallel. Each group of scissor mechanisms 3 includes a first fork arm 30 and a second fork arm 31. The upper end of the first fork arm 30 is connected to the lifting platform 4 through a rotating pair, and the upper end of the second fork arm 31 is connected to the lifting platform 4 through a moving pair; the lower end of the first fork arm 30 is connected to the base 1 through a moving pair, and the lower end of the second fork arm 31 is connected to the base 1 through a rotating pair. The middle parts of the first fork arm 30 and the second fork arm 31 are connected through a rotating pair; the above-mentioned moving pair includes a slider 32 and a slide rail 33 connected in a sliding manner. The slide rails 33 are respectively fixed on the base 1 and the lifting platform 4. The lower end of the first fork arm 30 is connected to the first slider and thus connected to the base 1, and the upper end of the second fork arm 31 is connected to the second slider and thus connected to the lifting platform 4.

[0056] Above the lifting platform 4, there is a load platform 5. A number of load sensors 42 connected to the control system by signals are arranged between the load platform 5 and the lifting platform 4. The control system obtains the total weight of the load platform 5 and its load by collecting the detection information of the load sensors 42, so as to determine the output power of the driving motor. Among them, load sensors 42 are arranged at the four corners of the lifting platform 4, and the load platform 5 is supported and connected through the load sensors 42. A pose sensor 41 connected to the control system by signals is also arranged on the upper surface of the lifting platform.

[0057] As Figures 2 - 3 shown, the chain 21 includes outer link sections 211 and inner link sections 212 alternately connected by connecting shafts, and a limiting mechanism. The inner link sections 212 are fixed to the connecting shafts, and the outer link sections 211 can rotate around the connecting shafts. The limiting mechanism includes a first limiting mechanism on the inner link sections 212 and a second limiting mechanism on the outer link sections 211. The first limiting mechanism includes a number of limiting baffles 2121 integrally formed with the inner link sections 212. The limiting baffles 2121 are located on the side of the inner link sections facing away from the sprockets, restricting the rotation of adjacent outer link sections in the first direction. Specifically, 4 limiting baffles 2121 are provided, respectively located in the tangential directions of the curved surfaces at the four corners on the outside of the inner link sections 212, and parallel to the center connection line of the two connecting shafts of the inner link sections 212. The limiting baffles 2121 have sufficient width and length to extend to the outer side walls of adjacent outer link sections 211, and stop and limit the adjacent outer link sections 211.

[0058] The second limiting mechanism of the outer link sections 211 includes a ratchet wheel 2122, a pawl 2111 and a spring 2112. The pawl 2111 is connected to the outer link section 211 through a rotating pair. One end of the spring 2112 is fixed to the outer link section 211, and the other end abuts against the pawl 2111. The ratchet wheel 2122 is fixedly connected to the connecting shaft. The separation and abutment of the pawl 2111 and the ratchet wheel 2122 are realized through the abutment and separation of the other row of teeth of the double-row sprocket 22 that does not mesh with the chain, so as to unlock or limit the rotation of the outer link section 211 in the second direction; the second direction is opposite to the first direction. Among them, the first direction can be regarded as the direction in which the chain radially moves away from the sprocket, and the second direction can be regarded as the direction in which the chain radially moves towards the sprocket, or, Figure 1 taking the right sprocket in

[0059] As

[0060] Figure 2As shown, when the chain and sprocket are not engaged, the chain link is in a locked state. Under the restoring force of the spring 2112, the pawl 2111 contacts the ratchet 2122, restricting the rotation of the outer chain link 211 and preventing it from rotating around the second direction. Under the action of the limit baffle 2121, the outer chain link 211 cannot rotate around the first direction, and the chain link is in a self-locking state. This state macroscopically corresponds to the vertical lifting section of the chain and the storage section inside the base. As Figure 3 described, when the chain and sprocket are engaged, the chain link is in an unlocked state. The row of teeth abuts against the pawl 2111 to separate the pawl 2111 from the ratchet 2122, unlocking the rotation of the outer chain link 211 in the second direction and enabling the chain to rotate with the sprocket for transmission.

[0061] As

[0062] Figure 4 shown, the hardware composition of the control system of the present invention is as follows. The remote controller sends instructions to the main controller through the wireless communication module. The main controller controls the left and right drive motors to rotate, and the encoder feeds back the motor rotation data. Before lifting and during operation, the load sensor and the displacement sensor collect the data of the lifting platform and feedback it to the main controller through the signal receiving module. All the above units / modules are powered by the charge-discharge and battery management unit composed of the battery pack.

[0063] As Figure 5 shown, the control flow example of the present invention is as follows. First, the load sensor 42 detects the total weight borne above the lifting platform and determines the motor drive power and speed in combination with the preset lifting speed. The total weight M of the load platform and its load, the set lifting speed v, the total output power P of the drive motor, and the sprocket speed n satisfy the following formula:

[0064]

[0065] M = M1 + M2 + M3 + M4 (2);

[0066]

[0067] where M0 is the weight of the lifting platform; v is the set lifting speed; f is the transmission efficiency, and f is 0.8 - 0.9; M1 - M4 are the weight values detected by the four load sensors; z is the number of teeth of the sprocket; d is the chain pitch, in mm; n is the sprocket speed, in r / min; t is the lifting time, α is the elastic modulus of the first fork arm or the second fork arm, L is the length of the first fork arm or the second fork arm, and T is the moment of inertia of the first fork arm or the second fork arm. The transmission efficiency is an empirical value obtained through multiple experiments considering the corresponding losses such as the self-weight of the chain, system friction, and heat energy loss. The system can be selected and corrected according to conditions such as the total load weight and the lifting speed.

[0068] Before the lifting platform 4 reaches the target height position, the pose sensor 41 measures the platform pose in real time to maintain the stability and operation safety of the lifting platform 4. After the lifting platform 4 reaches the target height, the motor stops rotating and locks.

[0069] The operation method of the lifting platform of the present invention includes the following steps:

[0070] 1) Place the object to be lifted on the lifting platform 4;

[0071] 2) During lifting: The load sensor 42 detects the total load weight. The control system calculates the total motor drive power and the motor speed according to the detection information of the load sensor 42 and the set lifting speed; the motor drives the sprocket to rotate, conveys the chain engaged with the sprocket upward, restricts the relative rotation of the adjacent inner and outer chain links of the chain through the limiting mechanism, ensures the vertical lifting movement of the chain, and realizes the lifting of the object.

[0072] In step 2), a double-row sprocket 22 is used for the sprocket. When the storage section chain 21 accommodated inside the base 1 feeds and contacts the double-row sprocket 22, one row of teeth of the double-row sprocket 22 meshes with the chain 21, and the other row of teeth pushes the pawl 2111 to separate from the ratchet 2122. The outer chain link 211 can rotate along the circumferential direction of the sprocket with the sprocket, and the chain link is in an unlocked state; when the chain 21 leaves the double-row sprocket 22 and enters the vertical lifting section, the pawl 2111 separates from the double-row sprocket 22, and the restoring force of the spring 2112 presses the pawl 2111 against the ratchet 2122, and the chain link is locked in the second direction; with the cooperation of the limiting baffle 2121, the outer chain link 211 cannot rotate in the first direction either, and the chain 21 is conveyed in a double-direction self-locking manner.

[0073] 3) During descent: The double-row sprocket 22 rotates in the reverse direction. When the double-direction self-locking chain 21 in the lifting section runs downward and contacts the double-row sprocket 22, one row of teeth of the double-row sprocket 22 meshes with the chain 21, and the other row of teeth pushes the pawl 2111 to separate from the ratchet 2122. The outer chain link 211 can rotate along the circumferential direction of the sprocket with the sprocket, and the chain link is in an unlocked state; when the chain 21 leaves the double-row sprocket 22 and enters the storage section, the pawl 2111 separates from the double-row sprocket 22, and the restoring force of the spring 2112 presses the pawl 2111 against the ratchet 2122, and the chain 21 is horizontally conveyed in a double-direction self-locking manner again. Thereafter, under the unlocking action of the storage sprocket in the bottom cavity, the horizontally conveyed chain 21 realizes bending and winding storage.

[0074] The above specific embodiments are only for explaining the technical concept and structural features of the present invention, aiming to enable those skilled in the relevant art to implement it accordingly. However, the above content does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A chain-driven large telescopic ratio constant force lifting platform, characterized in that, It includes a base, a scissor mechanism, a lifting platform, a chain lifting mechanism and a control system; The scissor mechanism is respectively connected between the base and the lifting platform through a rotating pair and a sliding pair; The chain lifting mechanism includes at least one sprocket installed on the base and its driving motor, and the driving motor is electrically connected to the control system; the sprocket meshes with the chain, and the top of the chain is connected to the bottom of the lifting platform through a rotating pair; The chain includes alternately connected inner chain links and outer chain links, and a limiting mechanism; the limiting mechanism includes a first limiting mechanism and a second limiting mechanism that respectively limit the opposite rotation directions of adjacent inner chain links and outer chain links, and bidirectionally lock the chain during the lifting movement in the vertical direction; The first limiting mechanism includes a number of limiting baffles integrally formed with the inner chain link or the outer chain link, and the limiting baffles are located on the side of the inner chain link or the outer chain link facing away from the sprocket, restricting the rotation of adjacent inner chain links and outer chain links in the first direction; The inner chain link and the outer chain link are rotationally connected through a connecting shaft, and the inner chain link is fixed to the connecting shaft; The second limiting mechanism includes a ratchet, a pawl and an elastic member, the ratchet is fixed on the connecting shaft, the pawl is rotatably fixed on the outer chain link, and one end of the elastic member is fixed on the outer chain link and the other end abuts against the pawl; the separation and abutment of the pawl and the ratchet are respectively realized through the abutment and separation of the sprocket teeth and the pawl, so as to unlock or restrict the rotation of the outer chain link in the second direction; the second direction is opposite to the first direction.

2. The large telescopic ratio constant force lifting platform according to claim 1, characterized in that, The scissor mechanism includes a first fork arm and a second fork arm. The upper end of the first fork arm is connected to the lifting platform through a rotating pair, and the upper end of the second fork arm is connected to the lifting platform through a sliding pair; the lower end of the first fork arm is connected to the base through a sliding pair, and the lower end of the second fork arm is connected to the base through a rotating pair.

3. The large telescopic ratio constant force lifting platform according to claim 1, characterized in that, The sprocket is a double-row sprocket, one row of teeth meshes with the chain, and the other row of teeth cooperates with the pawl.

4. The large telescopic ratio constant force lifting platform according to claim 3, characterized in that, The chain lifting mechanism includes at least two double-row sprockets; a vertical guide plate fixed on the upper surface of the base is provided on the side of the chain facing away from the double-row sprockets, and the height H of the vertical guide plate and the radius R of the double-row sprockets satisfy: R ≤ H ≤ 2R.

5. The large telescopic ratio constant force lifting platform according to claim 3 or 4, characterized in that A load platform is provided above the lifting platform, and a number of load sensors signal-connected to the control system are arranged between the load platform and the lifting platform. The control system obtains the total weight of the load platform and its load by collecting the detection information of the load sensors, so as to determine the output power of the driving motor.

6. The large stretch ratio constant force lifting platform according to claim 5, characterized in that, Load sensors are arranged at the four corners of the lifting platform, and the load platform is supported and connected through the load sensors.

7. The large telescopic ratio constant force lifting platform according to claim 5, characterized in that, It also includes a pose sensor signal-connected to the control system, which is used to detect the pose information of the lifting platform.

8. A running method of a chain-driven large-stroke constant-force lifting platform according to any one of claims 1-7, comprising the following steps: Place the object to be lifted on the lifting platform; The driving motor drives the sprocket to rotate, conveys the chain meshing with the sprocket upward, and restricts the relative rotation of adjacent inner chain links and outer chain links of the chain through the limiting mechanism to ensure the lifting movement of the chain in the vertical direction and realize the lifting of the object.

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