Height measuring structure for a lifting device and scissor fork lifting device

Abstract

The application 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 pulley, 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, the other end is sequentially connected to the winding motor after passing through the encoder pulley and the spring tightening assembly, and is kept engaged with the encoder pulley. The encoder calculates the height change by detecting the number of rotations of the pulley, realizes real-time measurement with high precision, and avoids the cumulative error of traditional screw transmission. The spring tightening assembly is externally elastically connected and can be lifted up and down, and dynamically adjusts the tension of the synchronous belt. When the assembly moves up to the highest position, the winding motor unwinds; when it moves down to the lowest position, the winding motor winds, always keeps the synchronous belt moderately tensioned, and adapts to a higher lifting stroke. The overall structure is compact and reasonable, convenient to install, and improves the measurement precision, stability and application range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lifting devices, and particularly relates to a height measuring structure for a lifting device and a scissor fork lifting device. BACKGROUND

[0002] In the prior art, a lifting mechanism usually adopts a motor combined with a screw rod transmission mode to realize vertical positioning of a workbench. However, the core defect of this mode is that the lifting precision is affected by multiple error factors: the pitch processing error of the screw rod itself, the coaxiality and perpendicularity deviation in the assembly process, and the wear and thermal deformation generated in long-term operation, which all introduce systematic errors that are difficult to eliminate. These errors are continuously accumulated in the continuous reciprocating lifting process, causing the positioning deviation to gradually expand, which cannot meet the strict requirements of high-precision application scenarios for position accuracy and repeat accuracy, and a height measuring structure adaptable to various lifting mechanisms needs to be designed. In addition, the screw rod lifting device needs to reserve a certain stroke below the platform according to the height of the platform, which will result in a high overall height of the equipment, and the use is limited for some application scenarios with limited height in the production workshop. SUMMARY

[0003] In order to overcome the above shortcomings, the purpose of the present application is to provide a height measuring structure for a lifting device and a scissor fork lifting device to solve the technical problem that the traditional screw rod lifting mechanism is difficult to eliminate the machining and assembly errors, resulting in cumulative positioning errors in the lifting process, and cannot meet the positioning requirements of high-precision applications.

[0004] To achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows:

[0005] A height measuring structure for a lifting device, characterized in that it comprises a connecting plate, an encoder pulley, an encoder, a spring tightening assembly, a winding motor and a synchronous belt; the connecting plate is used to connect an external lifting panel; the encoder pulley and the spring tightening assembly are both rotatably arranged; one end of the synchronous belt is connected to the connecting plate, the other end is connected to the winding motor after forming an upward-opening arc-shaped structure by passing through the spring tightening assembly, and the middle section is engaged with the encoder pulley; the encoder is connected with the encoder pulley to calculate the number of revolutions; the spring tightening assembly is externally elastically connected and can be lifted up and down; when the connecting plate rises with the lifting panel, the synchronous belt pulls the spring tightening assembly to move upward; when the connecting plate descends with the lifting panel, the spring tightening assembly tightens the synchronous belt downward; the winding motor unwinds the synchronous belt when the spring tightening assembly moves to the highest position, and winds the synchronous belt when the spring tightening assembly moves to the lowest position.

[0006] The application realizes real-time and accurate measurement of the lifting height through the cooperation of the synchronous belt and the encoder, effectively avoiding the cumulative error problem in the traditional screw transmission. The spring tightening assembly cooperates with the winding motor to dynamically adjust the tension of the synchronous belt: when the spring tightening assembly moves up to the highest position, the upper limit is triggered, and the winding motor unwinds the synchronous belt to avoid the synchronous belt being too tight and being pulled off; when the spring tightening assembly moves down to the lowest position, the lower limit is triggered, and the winding motor winds the synchronous belt to avoid the synchronous belt being too loose and causing too large measurement error. The intervention of the winding motor resets the effective working stroke of the spring through the winding and unwinding action, so that the synchronous belt can be adapted to devices with higher lifting height on the premise of ensuring that the synchronous belt is always in a moderate tension state. The overall structure is compact and reasonable, easy to install, and significantly improves the measurement accuracy, stability and application range of the lifting mechanism.

[0007] In some embodiments, a transition wheel rotatably arranged is further included, the transition wheel and the winding motor are located on opposite sides above the spring tightening assembly, and the encoder pulley is arranged below the side of the transition wheel away from the winding motor; after the synchronous belt is led out from the connecting plate, it is wound around the encoder pulley, the transition wheel, the spring tightening assembly and the winding motor in sequence to form a W-shaped structure.

[0008] The W-shaped layout makes the synchronous belt form a stable wrap angle at the spring tightening assembly, ensuring that it can be smoothly pulled upward; at the same time, it also increases the wrap angle of the synchronous belt on the encoder pulley, making it engage tightly and effectively preventing tooth skipping or slipping, thereby improving the measurement accuracy.

[0009] In some embodiments, a transition wheel rotatably arranged is further included, the encoder pulley and the winding motor are located on opposite sides above the spring tightening assembly, and the transition wheel is arranged below the side of the encoder pulley away from the winding motor; after the synchronous belt is led out from the connecting plate, it is wound around the transition wheel, the encoder pulley, the spring tightening assembly and the winding motor in sequence to form a W-shaped structure.

[0010] This structure not only ensures that the synchronous belt can stably and vertically pull the spring tightening assembly, with better movement stability; it also ensures that the synchronous belt and the encoder pulley are always in close contact, effectively avoiding counting errors caused by poor engagement, further improving the accuracy of height measurement.

[0011] In some embodiments, the transition wheel and the winding motor are located on opposite sides above the spring tightening assembly, so that the synchronous belt forms an arc structure after being wound around the spring tightening assembly.

[0012] The layout of the transition wheel and the winding motor makes the synchronous belt form an arc structure after being wound around the spring tightening assembly, which can stably pull the spring tightening assembly to move upward, enhancing the movement stability and rigidity of the mechanism.

[0013] In some embodiments, the spring tightening assembly comprises a vertically extending guide rail, a sliding seat in sliding cooperation with the guide rail, a tightening wheel rotatably arranged on the sliding seat, and a spring having one end connected to the base of the lifting device and the other end connected to the sliding seat.

[0014] In some embodiments, the spring tightening assembly further comprises first and second limiting devices symmetrically arranged at the upper and lower ends of the guide rail respectively, for triggering the unwinding or winding of the synchronous belt by the winding motor when the sliding seat is sensed to move to the position corresponding thereto.

[0015] Another aspect of the present application provides a scissor fork lifting device, comprising a base, two fork-shaped supports symmetrically arranged on both sides of the base, a lifting panel, and a driving device, each fork-shaped support comprising a first leg and a second leg hingedly connected to each other, the lower end of the first leg being hingedly connected to the base, the upper end of the first leg being in sliding cooperation with the lifting panel, the lower end of the second leg being in sliding cooperation with the base, and the upper end of the second leg being hingedly connected to the lifting panel, the driving device being drivingly connected to the lower end of the second leg of each fork-shaped support for driving the sliding of the fork-shaped supports on the base to fold or unfold the two fork-shaped supports.

[0016] The lifting device combines the high stability and compactness of the scissor fork structure with the high-precision measurement unit described above, realizes real-time detection and feedback control of the height during lifting, and greatly improves the positioning accuracy and motion stability. At the same time, the scissor fork structure effectively reduces the overall height of the equipment, so that it can also be applied in limited installation space, which is convenient for workers to operate and reduces the safety risks caused by the high equipment. It is particularly suitable for high-precision manufacturing and detection equipment, has a wide application prospect and good compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a front view of the first embodiment of the height measurement structure for the lifting device of the present application;

[0018] Figure 2 is a front view of the second embodiment of the height measurement structure for the lifting device of the present application;

[0019] Figure 3 is a side view of the height measurement structure for the lifting device of the present application;

[0020] Figure 4 is a sectional view of the height measurement structure for the lifting device of the present application installed on the scissor fork lifting device.

[0021] REFERENCE NUMERALS:

[0022] 1, connecting plate; 2, encoder pulley; 3, spring tightening assembly; 31, guide rail; 32, sliding seat; 33, tightening wheel; 34, spring; 4, winding motor; 5, synchronous belt; 6, transition wheel; 7, base; 8, fork support; 801, first leg; 802, second leg; 9, lifting panel; 10, driving device; 11, threaded seat. DETAILED DESCRIPTION

[0023] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with reference to specific embodiments and drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0024] The height measuring structure for lifting device provided by the present application mainly comprises a connecting plate 1, an encoder pulley 2, an encoder, a spring tightening assembly 3, a winding motor 4 and a synchronous belt 5. The connecting plate 1 is fixedly installed on the lower surface of the external lifting panel 9 by bolts and synchronously moves with the lifting panel 9, and the connecting plate 1 is preferably made of a metal plate with a thickness of about 5 mm to ensure the connection strength. The encoder pulley 2 is rotatably arranged on the base 7 of the lifting device by a bearing, the spring tightening assembly 3 is rotatably arranged and can move up and down in the vertical direction, the spring tightening assembly 3 is elastically connected to the external base 7 by an elastic element, one end of the synchronous belt 5 is fixedly connected to the connecting plate 1, the other end of the synchronous belt 5 sequentially passes through the spring tightening assembly 3 and forms an arc structure with the opening upward, and finally is connected to the output shaft of the winding motor 4. It is worth noting that the synchronous belt 5 is in meshing state with the encoder pulley 2. The encoder is coaxially connected with the encoder pulley 2, and the height change is calculated in real time by detecting the number of rotations of the pulley.

[0025] When the connecting plate 1 rises with the lifting panel 9, the synchronous belt 5 is pulled and drives the spring tightening assembly 3 to move upward, and when the connecting plate 1 descends, the spring tightening assembly 3 pulls the synchronous belt 5 downward under the action of the elastic restoring force, so that the synchronous belt 5 is always kept tensioned. Further, the winding motor 4 automatically performs the unwinding action when the spring tightening assembly 3 moves to the highest position, prevents the synchronous belt 5 from being too tight and broken, and performs the winding action when it moves to the lowest position, avoids the measurement error caused by the relaxation of the synchronous belt 5. In this way, the overall structure not only realizes high-precision and non-accumulative-error height measurement, but also adapts to larger lifting stroke through dynamic tension adjustment.

[0026] Preferably, the present application adds a transition wheel 6, and the transition wheel 6 has two setting directions, which are specifically as follows:

[0027] Please refer to Figure 1The first embodiment: the transition wheel 6 and the winding motor 4 are arranged on the left and right opposite sides above the spring tightening assembly 3 respectively, and the encoder pulley 2 is arranged below the side of the transition wheel 6 away from the winding motor 4. After the synchronous belt 5 is led out from the connecting plate 1, it is wound through the encoder pulley 2, the transition wheel 6, the spring tightening assembly 3 and the winding motor 4 in sequence, thereby forming a stable W-shaped transmission path. In particular, the layout makes the synchronous belt 5 form a proper wrap angle at the spring tightening assembly 3, ensures that it can be smoothly pulled upward, and at the same time increases the meshing area of the synchronous belt 5 and the encoder pulley 2, effectively prevents tooth skipping or slipping, and further improves the measurement accuracy and reliability.

[0028] Please refer to Figure 2 The second embodiment: the encoder pulley 2 and the winding motor 4 are located on the opposite sides above the spring tightening assembly 3 respectively, and the transition wheel 6 is arranged below the side of the encoder pulley 2 away from the winding motor 4. After the synchronous belt 5 is led out from the connecting plate 1, it is wound through the transition wheel 6, the encoder pulley 2, the spring tightening assembly 3 and the winding motor 4 in sequence, and also forms a W-shaped structure. Preferably, the relative positions of the transition wheel 6 and the winding motor 4 make the synchronous belt 5 form an arc-shaped trajectory after being wound through the spring tightening assembly 3, which not only ensures the stability of the synchronous belt 5 pulling the spring tightening assembly 3 vertically, but also further optimizes the transmission stability, effectively avoiding the counting error caused by poor meshing.

[0029] The spring tightening assembly 3 of the application specifically comprises: a vertically extending guide rail 31, a sliding seat 32 in sliding cooperation with the guide rail 31, a tightening 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 on the base 7 by bolts; the sliding seat 32 is in cooperation with the guide rail 31 through a sliding block and can slide up and down thereon; the tightening wheel 33 is mounted on the sliding seat 32 through a bearing, and the synchronous belt 5 is wound 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, as shown in Figure 3 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 synchronous belt 5 changes in force, the sliding seat 32 can move up and down along the guide rail 31, and the tension of the synchronous belt 5 is automatically adjusted through the expansion and contraction of the spring 34, ensuring the stability and accuracy of the measurement process.

[0030] In order to realize the unwinding of the synchronous belt 5 when the winding motor 4 moves to the highest position on the spring tightening assembly 3, and the winding of the synchronous belt 5 when the winding motor 4 moves to the lowest position, the present application is provided with a first limiting device and a second limiting device, which are symmetrically arranged at the upper and lower ends of the guide rail 31 respectively. These limiting devices preferably adopt proximity switches or mechanical limiters, and are electrically connected with the controller, which controls the action 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 controls the winding motor 4 to rotate and unwind the synchronous belt 5; 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 controls the winding motor 4 to perform the winding action. Through this limiting control mechanism, the working stroke of the spring tightening assembly 3 can be automatically reset, ensuring that the synchronous belt 5 is always in a moderate tension state, avoiding measurement failure or component damage caused by stroke limit.

[0031] It is worth noting that when the sliding seat 32 is at the middle position of the stroke of the guide rail 31, the tension of the synchronous belt 5 is most appropriate - neither too tight to cause additional load, nor too loose to affect the measurement accuracy. In order to achieve this state, the control logic of the winding motor 4 is specially designed: when any limiting device is triggered, the winding motor 4 performs a short (5 seconds) winding or unwinding action according to the limiting signal, so that the sliding seat 32 can move away from the limiting position. Such design can not only ensure that the synchronous belt 5 always maintains appropriate tension, but also avoid energy waste and mechanical wear caused by excessive operation of the motor, thereby improving the reliability and service life of the system while ensuring the measurement accuracy.

[0032] Please refer to Figure 4 The present application also provides a scissor fork lifting device integrating the above height measurement structure. The device includes a base 7, a pair of symmetrically arranged fork supports 8, a lifting panel 9 and a driving device 10. The fork support 8 is composed of a first leg 801 and a second leg 802, and the two legs are connected through a hinge point at the middle part, forming a retractable X-shaped structure. The lower end of the first leg 801 is hinged to the base 7, and the upper end is slidingly connected to the lifting panel 9. The lower end of the second leg 802 is slidingly connected to the base 7, and the upper end is hinged to the lifting panel 9. A threaded fitting seat 11 is arranged between the lower ends of the two fork supports 8. The driving device 10 adopts a hydraulic cylinder or an electric push rod, and its driving end is connected with the threaded fitting seat 11 through threads. When the driving device 10 is started, it can synchronously push the second legs 802 of the two fork supports 8 to slide horizontally along the base 7. The second legs 802 of the two fork supports 8 slide synchronously, and through the folding and unfolding movement of the fork supports 8, the lifting panel 9 is driven to realize stable vertical lifting.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] In addition to servo motors, the winding motor 4 can also be a DC motor with encoder feedback to reduce costs.

[0038] 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 the highest position and winds the synchronous belt (5) when it moves to the lowest position. The spring tensioning assembly (3) 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). 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). It also includes: first and second limiting devices respectively symmetrically disposed at the upper and lower ends of the guide rail (31), which are used to trigger the winding motor (4) to rotate to unwind or wind the synchronous belt (5) when the sliding seat (32) is moved to its corresponding 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. A scissor lift device, characterized in that, The height measuring structure as described in any one of claims 1–3 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).

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