Height measuring structure for lifting device and scissor fork lifting device

Abstract

The invention discloses a height measuring structure for a lifting device and a scissor fork lifting device, and belongs to the technical field of lifting devices. The structure comprises a connecting plate, an encoder belt wheel, an encoder, a spring tightening assembly, a winding motor and a synchronous belt. The connecting plate is connected with an external lifting panel; one end of the synchronous belt is fixed to the connecting plate, and the other end of the synchronous belt sequentially bypasses the encoder belt wheel and the spring tightening assembly, then is connected to the winding motor and is engaged with the encoder belt wheel. The encoder calculates the height change by detecting the number of rotation turns of the belt wheel, high-precision real-time measurement is achieved, and accumulative errors of traditional lead screw transmission are avoided. The spring tightening assembly is elastically connected with the outside and can ascend and descend to dynamically adjust the tension of the synchronous belt. When the assembly moves upwards to the highest position, the winding motor unwinds; and when the synchronous belt moves downwards to the lowest position, the winding motor conducts winding, the synchronous belt is always kept tensioned moderately, and the synchronous belt adapts to a higher lifting stroke. The overall structure is compact and reasonable, installation is convenient, and measurement precision, stability and application range are improved.

Description

Technical Field

[0001] This invention belongs to the field of lifting device technology, and particularly relates to a height measuring structure for lifting devices and a scissor lift device. Background Technology

[0002] In existing technologies, lifting mechanisms typically employ a combination of a motor and a lead screw drive to achieve vertical positioning of the worktable. However, the core drawback of this method lies in the fact that lifting accuracy is affected by multiple error factors: machining errors in the lead screw pitch, coaxiality and perpendicularity deviations during assembly, and wear and thermal deformation generated during long-term operation all introduce systemic errors that are difficult to eliminate. These errors accumulate continuously during reciprocating lifting, leading to a gradual increase in positioning deviation. This fails to meet the stringent requirements for positional accuracy and repeatability in high-precision applications, necessitating the design of a height measurement structure adaptable to various lifting mechanisms. Furthermore, the amount of travel required for the lead screw lifting device to raise the platform dictates the amount of travel below, resulting in a relatively high overall height of the equipment. This limits its use in applications with limited height, such as production workshops. Summary of the Invention

[0003] To overcome the above shortcomings, the present invention aims to provide a height measuring structure for a lifting device and a scissor fork lifting device, so as to solve the technical problem that the traditional screw lifting mechanism is difficult to eliminate due to processing and assembly errors, resulting in cumulative positioning errors during the lifting process, which cannot meet the positioning requirements of high-precision applications.

[0004] To achieve the above objectives, this application provides the following technical solution: A height measuring structure for a lifting device, characterized in that it comprises: a connecting plate, an encoder pulley, an encoder, a spring tensioning assembly, a winding motor, and a synchronous belt; the connecting plate is used to connect to an external lifting panel; both the encoder pulley and the spring tensioning assembly are rotatably mounted; one end of the synchronous belt is connected to the connecting plate, and the other end passes around the spring tensioning assembly to form an upward-opening arc structure before connecting to the winding motor, with its middle section meshing with the encoder pulley; the encoder is linked to the encoder pulley to calculate its rotation count; the spring tensioning assembly is elastically connected to the external device and can move up and down; when the connecting plate rises with the lifting panel, the synchronous belt pulls the spring tensioning assembly upward; when the connecting plate falls with the lifting panel, the spring tensioning assembly pulls the synchronous belt downward; the winding motor unwinds the synchronous belt when the spring tensioning assembly reaches its highest position and winds it up when it reaches its lowest position.

[0005] This application achieves real-time and accurate measurement of lifting height through the cooperation of a synchronous belt and an encoder, effectively avoiding the cumulative error problem in traditional lead screw drives. The spring tensioning assembly and the winding motor work together to dynamically adjust the synchronous belt tension: when the spring tensioning assembly moves to its highest position, it triggers the upper limit switch, and the winding motor unwinds the synchronous belt to prevent it from breaking due to excessive tension; when the spring tensioning assembly moves to its lowest position, it triggers the lower limit switch, and the winding motor winds the synchronous belt to prevent it from becoming too loose and causing excessive measurement error. The intervention of the winding motor resets the effective working stroke of the spring through the winding and unwinding actions, thus ensuring that the synchronous belt is always under appropriate tension, allowing it to adapt to devices with higher lifting heights. The overall structure is compact and reasonable, easy to install, and significantly improves the measurement accuracy, stability, and applicability of the lifting mechanism.

[0006] In some embodiments, a rotatable transition wheel is also included, with the transition wheel and the winding motor located on opposite sides above the spring tensioning assembly, and the encoder pulley located below the transition wheel on the side away from the winding motor; the synchronous belt is led out from the connecting plate and sequentially passes through the encoder pulley, the transition wheel, the spring tensioning assembly and the winding motor to form a W-shaped structure.

[0007] The W-shaped layout allows the synchronous belt to form a stable wrap angle at the spring tensioning assembly, ensuring that it can be pulled upwards smoothly. At the same time, it also increases the wrap angle of the synchronous belt on the encoder pulley, making it mesh tightly and effectively preventing tooth skipping or slippage, thereby improving measurement accuracy.

[0008] In some embodiments, a rotatable transition wheel is also included, with the encoder pulley and the winding motor located on opposite sides above the spring tensioning assembly, and the transition wheel located below the encoder pulley on the side away from the winding motor; after the synchronous belt is led out from the connecting plate, it passes sequentially around the transition wheel, the encoder pulley, the spring tensioning assembly and the winding motor to form a W-shaped structure.

[0009] This structure not only ensures that the synchronous belt can stably and vertically pull the spring tensioning assembly, resulting in better motion smoothness, but also ensures that the synchronous belt and the encoder pulley are always in close contact, effectively avoiding counting errors caused by poor meshing, and further improving the accuracy of height measurement.

[0010] In some embodiments, the transition pulley and the winding motor are located on both sides above the spring tensioning assembly, so that the synchronous belt is wound around the spring tensioning assembly to form an arc-shaped structure.

[0011] The layout of the transition pulley and the winding motor allows the synchronous belt winding to form an arc-shaped structure after the spring tensioning assembly, which can stably pull the spring tensioning assembly upward, enhancing the smoothness of movement and the rigidity of the mechanism.

[0012] In some embodiments, the spring tensioning assembly includes: a vertically extending guide rail, a sliding seat that slides with the guide rail, a tensioning wheel rotatably disposed on the sliding seat, and a spring, one end of the spring being connected to the base of the lifting device and the other end being connected to the sliding seat.

[0013] In some embodiments, the system further includes: first and second limiting devices symmetrically disposed at the upper and lower ends of the guide rail, respectively, for triggering the winding motor to rotate to unwind or wind the synchronous belt when the sliding seat is sensed to move to its corresponding position.

[0014] Another aspect of the present invention provides a scissor lift device, comprising: a base, two fork-shaped supports symmetrically arranged on both sides of the base, a lift panel, and a drive device. Each fork-shaped support includes a first leg and a second leg hinged to each other. The lower end of the first leg is hinged to the base, and the upper end is slidably engaged with the lift panel. The lower end of the second leg is slidably engaged with the base, and the upper end is hinged to the lift panel. The drive device is driven to the lower end of the second leg of the two fork-shaped supports, for driving them to slide on the base to fold or unfold the two fork-shaped supports.

[0015] This lifting device combines the high stability and compactness of a scissor fork structure with the aforementioned high-precision measurement unit, enabling real-time height detection and feedback control during lifting, significantly improving positioning accuracy and motion smoothness. Simultaneously, the scissor fork structure effectively reduces the overall height of the equipment, making it suitable for use in limited installation spaces. This facilitates worker operation and reduces safety risks associated with excessive equipment height. It is particularly suitable for high-precision manufacturing and testing equipment, possessing broad application prospects and excellent compatibility. Attached Figure Description

[0016] Figure 1 This is a front view of the first embodiment of the height measuring structure for the lifting device of the present invention; Figure 2 This is a front view of the second embodiment of the height measuring structure for the lifting device of the present invention; Figure 3 This is a side view of the height measuring structure for the lifting device of the present invention; Figure 4 This is a cross-sectional view of the height measuring structure of the lifting device of the present invention installed on the scissor lift device.

[0017] Figure label: 1. Connecting plate; 2. Encoder pulley; 3. Spring tensioning assembly; 31. Guide rail; 32. Sliding seat; 33. Tensioning wheel; 34. Spring; 4. Rewinding motor; 5. Synchronous belt; 6. Transition pulley; 7. Base; 8. Fork-shaped bracket; 801. First support leg; 802. Second support leg; 9. Lifting panel; 10. Drive unit; 11. Threaded mating seat. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0019] This invention provides a height measurement structure for a lifting device, mainly comprising: a connecting plate 1, an encoder pulley 2, an encoder, a spring tensioning assembly 3, a winding motor 4, and a synchronous belt 5. The connecting plate 1 is bolted to the lower surface of an external lifting panel 9 and moves synchronously with it. The connecting plate 1 is preferably made of a metal plate with a thickness of approximately 5mm to ensure connection strength. The encoder pulley 2 is rotatably mounted on the base 7 of the lifting device via bearings. The spring tensioning assembly 3 is rotatably mounted and can move up and down vertically. The spring tensioning assembly 3 is elastically connected to the external base 7 via an elastic element. One end of the synchronous belt 5 is firmly connected to the connecting plate 1, and the other end passes around the spring tensioning assembly 3, forming an upward-opening arc structure, before finally connecting to the output shaft of the winding motor 4. Notably, the synchronous belt 5 maintains engagement with the encoder pulley 2. The encoder is directly coaxially connected to the encoder pulley 2, and the height change is calculated in real time by detecting the number of rotations of the pulley.

[0020] When the connecting plate 1 rises with the lifting panel 9, the synchronous belt 5 is stretched, causing the spring tensioning assembly 3 to move upward. When the connecting plate 1 descends, the spring tensioning assembly 3 pulls the synchronous belt 5 downward under the action of elastic restoring force, thus maintaining the tension of the synchronous belt 5 at all times. Furthermore, the winding motor 4 automatically performs the unwinding action when the spring tensioning assembly 3 moves to its highest position to prevent the synchronous belt 5 from breaking due to excessive tension, and performs the winding action when it moves to its lowest position to avoid measurement errors caused by the slack of the synchronous belt 5. In this way, the overall structure not only achieves high-precision height measurement without cumulative error, but also adapts to a larger lifting stroke through dynamic tension adjustment.

[0021] Preferably, this application adds a transition wheel 6, which has two setting positions, as detailed below: Please see Figure 1In the first embodiment: the transition pulley 6 and the take-up motor 4 are respectively arranged on opposite left and right sides above the spring tensioning assembly 3, while the encoder pulley 2 is located below the transition pulley 6 on the side away from the take-up motor 4. After the synchronous belt 5 is led out from the connecting plate 1, it sequentially passes through the encoder pulley 2, the transition pulley 6, the spring tensioning assembly 3, and the take-up motor 4, thus forming a stable W-shaped transmission path. Specifically, this arrangement allows the synchronous belt 5 to form an appropriate wrap angle at the spring tensioning assembly 3, ensuring it can be smoothly pulled upwards, while increasing the meshing area between the synchronous belt 5 and the encoder pulley 2, effectively preventing tooth skipping or slippage, thereby improving measurement accuracy and reliability.

[0022] Please see Figure 2 In the second embodiment: the encoder pulley 2 and the take-up motor 4 are located on opposite sides above the spring tensioning assembly 3, while the transition pulley 6 is positioned below the encoder pulley 2 on the side furthest from the take-up motor 4. After the synchronous belt 5 emerges from the connecting plate 1, it passes sequentially through the transition pulley 6, the encoder pulley 2, the spring tensioning assembly 3, and the take-up motor 4, also forming a W-shaped structure. Preferably, the relative positions of the transition pulley 6 and the take-up motor 4 cause the synchronous belt 5 to form an arc-shaped path after passing through the spring tensioning assembly 3. This not only ensures the stability of the synchronous belt 5 vertically pulling the spring tensioning assembly 3 but also further optimizes the transmission smoothness, effectively avoiding counting errors caused by poor meshing.

[0023] The spring tensioning assembly 3 of the present invention specifically includes: a vertically extending guide rail 31, a sliding seat 32 that slides with the guide rail 31, a tensioning wheel 33 rotatably mounted on the sliding seat 32, and a spring 34. The guide rail 31 is preferably made of metal profile and is vertically fixed to the base 7 by bolts; the sliding seat 32 engages with the guide rail 31 via a slider and can slide up and down along it; the tensioning wheel 33 is mounted on the sliding seat 32 via a bearing, and a synchronous belt 5 passes around the wheel to transmit tension; one end of the spring 34 is connected to the base 7 of the lifting device, and the other end is connected to the sliding seat 32, such as... Figure 3 As shown. Preferably, the spring 34 is a helical tension spring 34, and its stiffness is selected according to the required tension of the synchronous belt 5. In this way, when the force on the synchronous belt 5 changes, the sliding seat 32 can move up and down along the guide rail 31, and the tension of the synchronous belt 5 can be automatically adjusted by the extension and contraction of the spring 34, ensuring the stability and accuracy of the measurement process.

[0024] To ensure that the winding motor 4 unwinds the synchronous belt 5 when the spring tensioning assembly 3 is at its highest position and winds it up when it is at its lowest position, this invention includes a first limiting device and a second limiting device. Specifically, the first and second limiting devices are symmetrically arranged at the upper and lower ends of the guide rail 31, respectively. These limiting devices are preferably proximity switches or mechanical limiters, and are electrically connected to a controller, which controls the operation of the winding motor 4. When the sliding seat 32 moves to the corresponding position at the upper end of the guide rail 31, the first limiting device is triggered and sends a signal to the controller, which then controls the winding motor 4 to rotate and unwind the synchronous belt 5. Conversely, when the sliding seat 32 moves to the corresponding position at the lower end of the guide rail 31, the second limiting device is triggered, and the controller then controls the winding motor 4 to perform the winding action. This limiting control mechanism automatically resets the working stroke of the spring tensioning assembly 3, ensuring that the synchronous belt 5 is always under appropriate tension and preventing measurement failure or component damage due to stroke limits.

[0025] It is worth noting that the tension of the synchronous belt 5 is most suitable when the sliding seat 32 is in the middle position of the guide rail 31's travel—neither too tight, causing additional load, nor too loose, affecting measurement accuracy. To achieve this state, the control logic of the take-up motor 4 is specially designed: when any limit device is triggered, the take-up motor 4 performs a short (e.g., 5 seconds) take-up or unwind action according to the limit signal, causing the sliding seat 32 to disengage from the limit position. This design ensures that the synchronous belt 5 always maintains appropriate tension while avoiding energy waste and mechanical wear caused by excessive motor operation, thereby improving the system's reliability and service life while ensuring measurement accuracy.

[0026] Please see Figure 4 The present invention also provides a scissor-fork lifting device that integrates the aforementioned height measurement structure. The device includes a base 7, a pair of symmetrically arranged fork-shaped supports 8, a lifting panel 9, and a drive device 10. Each fork-shaped support 8 consists of a first leg 801 and a second leg 802, connected at the middle by a hinge point to form a retractable X-shaped structure. The lower end of the first leg 801 is hinged to the base 7, and its upper end is slidably connected to the lifting panel 9. The lower end of the second leg 802 is slidably engaged with the base 7, and its upper end is hinged to the lifting panel 9. A threaded engagement seat 11 is provided between the lower ends of the second legs 802 of the two fork-shaped supports 8. The drive device 10 uses a hydraulic cylinder or an electric push rod, and its drive end is threadedly connected to the threaded engagement seat 11. When the drive device 10 is activated, it synchronously pushes the second legs 802 of the two fork-shaped supports 8 to slide horizontally along the base 7. The synchronous sliding of the second legs 802 of the two fork-shaped supports 8, through the folding and unfolding motion of the fork-shaped supports 8, drives the lifting panel 9 to achieve smooth vertical lifting.

[0027] Specifically, in the height measurement structure, the connecting plate 1 is installed on the lower surface of the lifting panel 9 and moves synchronously with it. The other end of the synchronous belt 5 passes through the encoder pulley 2, the encoder, the spring tensioning assembly 3, and the transition pulley 6 before finally winding to the take-up motor 4. During the lifting process, the synchronous belt 5 is pulled or released, the encoder detects the change in the rotation angle of the encoder pulley 2, and the controller calculates the real-time height to achieve high-precision positioning.

[0028] Specifically, the encoder pulley 2 is directly connected to the encoder shaft, ensuring that the number of rotations of the pulley corresponds exactly to the number of rotations of the encoder. The encoder integrates a chip capable of accurately measuring the rotation angle of the pulley. In particular, this rotation angle, combined with the module of the encoder pulley 2 (i.e., the linear distance the synchronous belt 5 moves per rotation of the pulley), allows for the calculation of the linear displacement of the synchronous belt 5 in the vertical direction. For example, a 360-degree rotation of the pulley corresponds to a module-length movement of the synchronous belt 5; therefore, by measuring the rotation angle, the height change of the lifting panel 9 can be derived. This achieves high precision and real-time height measurement.

[0029] Preferably, the drive unit 10 can be a worm gear lift with reverse self-locking characteristics, forming a double anti-fall guarantee together with the braked winding motor 4. The lifting panel 9 can be a rectangular steel pipe welded frame supplemented with a steel plate table, balancing rigidity and lightweight.

[0030] In some implementations, the timing belt 5 can be replaced with a wire rope or chain, and the corresponding pulleys also need to be adapted accordingly; the encoder can also be an absolute type or a magnetic encoder to reduce the risk of position loss when power is off. In addition to metal guide rails 31, engineering plastic guide rails 31 can also be used to reduce weight and noise.

[0031] In addition to servo motors, the winding motor 4 can also be a DC motor with encoder feedback to reduce costs.

[0032] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A height measuring structure for a lifting device, characterized in that, include: The system comprises a connecting plate (1), an encoder pulley (2), an encoder, a spring tensioning assembly (3), a winding motor (4), and a synchronous belt (5); the connecting plate (1) is used to connect to an external lifting panel; the encoder pulley (2) and the spring tensioning assembly (3) are both rotatably mounted; one end of the synchronous belt (5) is connected to the connecting plate (1), and the other end passes around the spring tensioning assembly (3) to form an upward-opening arc structure before connecting to the winding motor (4), and it meshes with the encoder pulley (2); the encoder is linked to the encoder pulley (2) to calculate its rotation number; the spring tensioning assembly (3) is elastically connected to the external system and can be raised and lowered; When the connecting plate (1) rises with the lifting panel, the synchronous belt (5) pulls the spring tensioning assembly (3) upward; when the connecting plate (1) falls with the lifting panel, the spring tensioning assembly (3) pulls the synchronous belt (5) downward. The winding motor (4) unwinds the synchronous belt (5) when the spring tensioning assembly (3) moves to its highest position and winds the synchronous belt (5) when it moves to its lowest position.

2. The height measuring structure for the lifting device according to claim 1, characterized in that, It also includes a rotatable transition wheel (6), which is located on opposite sides above the spring tensioning assembly (3) and the winding motor (4). The encoder pulley (2) is located below the transition wheel (6) on the side away from the winding motor (4). The synchronous belt (5) is led out from the connecting plate (1) and passes through the encoder pulley (2), the transition wheel (6), the spring tensioning assembly (3) and the winding motor (4) in sequence to form a W-shaped structure.

3. The height measuring structure for the lifting device according to claim 1, characterized in that, It also includes a rotatable transition wheel (6), the encoder pulley (2) and the winding motor (4) are respectively located on opposite sides above the spring tensioning assembly (3), and the transition wheel (6) is located below the encoder pulley (2) on the side away from the winding motor (4); the synchronous belt (5) is led out from the connecting plate (1) and passes through the transition wheel (6), the encoder pulley (2), the spring tensioning assembly (3) and the winding motor (4) in sequence to form a W-shaped structure.

4. The height measuring structure for the lifting device according to claim 1, characterized in that, The spring tightening assembly (3) includes: a vertically extending guide rail (31), a sliding seat (32) that slides with the guide rail (31), a tightening wheel (33) rotatably mounted on the sliding seat (32), and a spring (34). One end of the spring (34) is connected to the base (7) of the lifting device, and the other end is connected to the sliding seat (32).

5. The height measuring structure for the lifting device according to claim 4, characterized in that, Also includes: The first and second limiting devices, respectively symmetrically arranged at the upper and lower ends of the guide rail (31), are used to trigger the winding motor (4) to rotate and unwind or wind the synchronous belt (5) when the sliding seat (32) is moved to its corresponding position.

6. A scissor lift device, characterized in that, The height measuring structure as described in any one of claims 1–4 further includes: a base (7), two fork-shaped supports (8) symmetrically arranged on both sides of the base (7), a lifting panel (9), and a driving device (10). Each fork-shaped support (8) includes a first leg (801) and a second leg (802) hinged to each other. The lower end of the first leg (801) is hinged to the base (7) and the upper end is slidably engaged with the lifting panel (9). The lower end of the second leg (802) is slidably engaged with the base (7) and the upper end is hinged to the lifting panel (9). The driving device (10) is driven to the lower end of the second leg (802) of the two fork-shaped supports (8) for driving them to slide on the base (7) to fold or unfold the two fork-shaped supports (8).

Images