Hoisting equipment cart stroke measuring device and application method

Abstract

The invention relates to the technical field of hoisting equipment, in particular to a hoisting equipment cart stroke measuring device and an application method.The hoisting equipment cart stroke measuring device comprises a transmission shaft, one end of the transmission shaft is provided with a flange plate used for connection, and the flange plate is coaxially and fixedly connected with the axle end face of a cart wheel of the hoisting equipment; the trolley body synchronously rotates along with the cart wheels; an input shaft of the encoder is in transmission connection with the other end of the transmission shaft, and the encoder is used for collecting rotation data of the transmission shaft and transmitting the rotation data to a safety monitoring system to calculate the stroke distance; and the encoder bracket is used for fixing a shell of the encoder on a non-rotating part of the hoisting equipment, so that the shell of the encoder is kept static when the transmission shaft rotates. Through rigid transmission connection and a dynamic self-calibration algorithm, the two technical problems of slipping and abrasion are solved, and long-term, reliable and high-precision stroke measurement is achieved.

Description

Technical Field

[0001] This invention relates to the field of lifting equipment technology, and more specifically, to a device for measuring the stroke of a crane trolley and its application method. Background Technology

[0002] Cranes, especially gantry cranes and bridge cranes, are indispensable key equipment in modern industrial production and logistics transportation. To ensure their safe operation, achieve automated control, and conduct precise work area management, real-time monitoring of the trolley's operating status is necessary. Among these parameters, the trolley's travel distance is a core critical parameter; its accuracy directly affects the reliability of the entire safety monitoring system and provides fundamental data support for advanced functions such as collision avoidance, endpoint limiting, and multi-crane collaborative operation. Therefore, developing a device and method capable of long-term, stable, and high-precision measurement of crane trolley travel is of great significance for improving the safety performance and intelligence level of modern cranes. Currently, there are inherent shortcomings in measuring trolley travel: on the one hand, most methods rely on indirect measurement using friction measuring wheels pressed against the rail or wheel surface. This method is highly susceptible to environmental factors such as rain, snow, oil, and dust, causing slippage or jamming between the measuring wheel and the contact surface, thus introducing unpredictable measurement errors. On the other hand, its calculation method usually relies on a fixed wheel diameter parameter, which not only fails to compensate for the wear of the measuring wheel itself, but also ignores the inevitable wear of the crane's trolley wheels during long-term use. This design flaw will lead to a continuous accumulation of errors in the stroke calculation, which seriously affects the long-term accuracy and reliability of the measurement. Summary of the Invention

[0003] The purpose of this invention is to provide a crane trolley stroke measurement device and application method, which solves the two major technical problems of slippage and wear through rigid transmission connection and dynamic self-calibration algorithm, and realizes long-term, reliable and high-precision stroke measurement.

[0004] This invention is achieved through the following technical solution: A crane trolley travel measuring device includes: a drive shaft, one end of which has a flange for connection, the flange being coaxially fixedly connected to the axle end face of the crane trolley wheel and rotating synchronously with the crane wheel; an encoder, the input shaft of which is drivenly connected to the other end of the drive shaft, for collecting rotation data of the drive shaft and transmitting the rotation data to a safety monitoring system to calculate the travel distance; and an encoder bracket, which fixes the encoder housing to a non-rotating part of the crane to keep the encoder housing stationary when the drive shaft rotates.

[0005] Optionally, the flange of the drive shaft is provided with multiple through holes, and the flange is fixed to the end cover of the wheel axle of the trolley by bolts passing through the through holes.

[0006] Optionally, the bolts are fixed using the existing bolt holes on the end cap to ensure the coaxiality of the drive shaft and the axle of the vehicle wheel.

[0007] Optionally, a coupling is provided between the drive shaft and the input shaft of the encoder for transmitting rotation.

[0008] Optionally, the coupling is a flexible coupling used to compensate for radial, axial, and angular alignment errors that occur between the drive shaft and the encoder input shaft during installation.

[0009] Optionally, the encoder bracket is a rigid metal plate structure, which includes a mounting part for mounting and fixing the encoder, and a fixing part for connecting the bracket itself to the non-rotating part of the lifting equipment.

[0010] Optionally, the fixing part of the encoder bracket is fixed to the trolley end beam of the lifting equipment.

[0011] Optionally, a central through hole is provided at the center of the end cover of the wheel axle of the large vehicle, and the drive shaft passes through the central through hole to drive the encoder.

[0012] Optionally, the encoder is an absolute encoder.

[0013] A method for applying a crane trolley stroke measuring device, wherein the device is applied to the crane trolley stroke measuring device, the method comprising the following steps: The flange of the drive shaft is coaxially fixedly connected to the end face of the wheel axle of the crane wheel, so that the drive shaft can rotate synchronously with the rotation of the crane wheel. The encoder collects rotational data of the drive shaft. During the data collection process, the encoder housing is fixed to the non-rotating parts of the lifting equipment by the encoder bracket to keep it stationary. The rotation data collected by the encoder is transmitted to the safety monitoring system, which then calculates the actual travel distance of the crane trolley based on the rotation data. The specific steps are as follows: The safety monitoring system has a preset initial pulse-distance conversion coefficient, which is based on the initial design diameter of the vehicle wheel. The safety monitoring system receives the number of pulses generated by the encoder and calculates the travel distance in real time by multiplying the number of pulses by the initial pulse-distance conversion coefficient. At least two calibration reference points are set at fixed positions on the track where the lifting equipment is running, and the actual physical distance between the two calibration reference points is stored in the safety monitoring system. When the safety monitoring system detects that the crane trolley is running completely between the two calibration reference points, a calibration process is triggered: the safety monitoring system records the total number of pulses output by the stroke encoder during this calibration. The safety monitoring system uses the actual physical distance of this calibration trip and the total number of pulses recorded to obtain a pulse-distance conversion coefficient that reflects the current wheel condition by dividing the actual physical distance by the total number of pulses. The safety monitoring system replaces the initial pulse-distance conversion coefficient with the calculated pulse-distance conversion coefficient, and uses this as the benchmark for all travel distance calculations. It repeats the process according to a preset cycle to achieve continuous dynamic compensation for wheel wear.

[0014] The technical solution of the present invention has at least the following advantages and beneficial effects: This invention achieves a coaxial rigid connection between the encoder and the trolley wheel axle through a drive shaft and flange, completely eliminating unstable friction transmission and fundamentally eliminating measurement errors caused by slippage or jamming, thus ensuring the absolute reliability of the raw data acquisition. Furthermore, this invention creatively proposes a dynamic self-calibration calculation method, which not only utilizes fixed reference points on the track to automatically learn and correct for the effects of wheel wear, but also forms an intelligent closed-loop measurement system, thereby ensuring long-term, continuous high accuracy of travel measurement throughout the entire equipment lifecycle. Attached Figure Description

[0015] Figure 1 A schematic diagram of the lead-out shaft provided by the present invention; Figure 2 This is a flowchart illustrating the application method of the crane trolley stroke measuring device provided by the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] like Figure 1As shown, this embodiment of the invention provides a crane trolley stroke measuring device and its application method. Specifically, the core design concept of the crane trolley stroke measuring device in this embodiment is to establish a stable, reliable mechanical transmission and signal acquisition system that is unaffected by external environmental interference. This device is mainly installed on the trolley part of the crane, such as the trolley end beam or trolley frame of a gantry crane or bridge crane.

[0018] Core transmission components: drive shaft and flange.

[0019] transmission shaft: Structure and Materials: The drive shaft is the core component for power transmission. In this embodiment, it is preferably made of high-strength, high-torsional-rigidity, and good-wear-resistant metal materials such as 45 steel or 40Cr, and undergoes quenching and tempering heat treatment to ensure that it will not deform or break under long-term high-load operation. Its shape is a solid or hollow cylindrical long shaft with a precision-machined surface, exhibiting good concentricity and surface finish to reduce vibration and friction loss during rotation. One end of the shaft is used to connect to a flange, and the other end is used to connect to the subsequent signal acquisition system.

[0020] Function and Positioning: The drive shaft's function is to transmit the rotational motion of the crane's trolley wheels in a 1:1 ratio without loss. It is the power source of the entire measurement chain.

[0021] Flange: Structure and Connection: The flange is a key interface component for connecting the device to the lifting equipment body. It is a disc-shaped metal part with several bolt holes evenly distributed on its surface for mounting and fixing. One end face (inner end face) of the flange is firmly fixed to one end of the drive shaft. This connection is preferably made by welding, by fully welding the contact area between the end of the drive shaft and the center hole of the flange to form a rigid whole, ensuring that there is no relative rotation between the two. Alternatively, a key connection or interference fit can also be used, as long as reliable torque transmission can be guaranteed.

[0022] Installation and Implementation of "Coaxial Fixed Connection": The other end face (outer end face) of the flange is used for fixed connection with the axle end face of the crane wheel. During installation, the original axle end cover of the crane wheel needs to be removed. The flange of this device is aligned with the center of the axle, and the flange is fastened to the axle end face using high-strength bolts through the pre-drilled bolt holes on the axle end face. The key here is to ensure that the central axis of the drive shaft is strictly coincident with the central axis of the crane wheel, thus achieving a "coaxial fixed connection." This connection method is the basis for the excellent technical effect of this invention. It makes the rotation of the drive shaft completely equivalent to the rotation of the crane wheel, eliminating the slippage and jumping problems that may exist with traditional friction wheels from a physical structure perspective.

[0023] Signal acquisition and support components: encoder, encoder bracket, bearing and bearing housing, coupling.

[0024] Encoder: Selection and Function: The encoder is the "heart" of the measurement system, responsible for converting mechanical angular displacement into electrical signals. In this embodiment, an absolute encoder is preferred. Compared to incremental encoders, absolute encoders can immediately output the current absolute position information even after the system is powered on again following a power outage, without needing to find a reference zero point. This is especially important for applications like lifting equipment that require high safety and power-off position memory. Encoder resolution is a key parameter; for example, a model with 4096 P / R (i.e., 4096 pulses or position codes per revolution) or higher resolution can be selected to ensure sufficient measurement accuracy. The encoder's output signal type can be parallel output, SSI serial synchronous interface, or industrial bus interfaces such as CANopen or Profinet for communication with a higher-level safety monitoring system (such as a PLC or industrial computer).

[0025] Installation location: The encoder shaft is connected to the drive shaft via a coupling, and its housing is fixed to the encoder bracket.

[0026] Encoder bracket: Structure and Materials: The encoder bracket serves as the mounting base for the entire device. It typically employs an L-shaped or Π-shaped welded steel plate structure, possessing sufficient strength and rigidity to resist vibrations and impacts during operation. The bracket has mounting holes for securing the bearing housing, the encoder, and itself to the lifting equipment.

[0027] Key Function – Providing a Stationary Reference Frame: A crucial function of the encoder bracket is that it must be securely fixed to a non-rotating component of the lifting equipment. This non-rotating component typically refers to the end beam of the trolley, the trolley frame, or other structural parts that do not rotate relative to the wheels. In this way, when the trolley wheels and drive shaft rotate, the encoder bracket, along with the encoder housing, bearing seats, and other components fixed to it, remains absolutely stationary. This allows relative rotation between the encoder shaft and the housing, enabling accurate measurement of the angle and number of rotations.

[0028] Bearings and bearing housings: Function: To ensure smooth, low-resistance rotation of the drive shaft, the device is equipped with bearings and bearing housings. The bearing housings are fixed to the encoder bracket, while the drive shaft passes through the bearing housings and is supported by internal bearings.

[0029] Selection: Typically, two deep groove ball bearings or angular contact bearings are used, distributed at both ends of the drive shaft, to simultaneously withstand radial and axial forces, ensuring that the drive shaft does not wobble or become eccentric during rotation. Bearing housings with sealing rings are preferred to prevent dust and moisture intrusion, extending the bearing's service life.

[0030] Coupling: Function: Couplings are used to connect the end of a drive shaft to the input shaft of an encoder. Their function is not only to transmit torque, but more importantly, to compensate for any minor misalignment (including angular, radial, and axial deviations) that may exist between the drive shaft and the encoder shaft, and to absorb some system vibrations, thus protecting this precision component from damage.

[0031] Selection: In this embodiment, a flexible coupling or a diaphragm coupling is preferred, as they have good elasticity and compensation capabilities.

[0032] Auxiliary protective components: protective shield.

[0033] Structure and Function: Considering that lifting equipment often operates outdoors or in harsh environments such as dust and humidity, this embodiment also includes a protective cover to protect the entire measuring device, especially the precision encoder and bearings. This protective cover is typically made of stamped and welded stainless steel or thick steel plate, and its shape is designed to completely cover all components except the flange. The protective cover is bolted to the encoder bracket and has a sealed joint at the cable outlet. Its protection level can reach IP65 or higher, effectively preventing the intrusion of rainwater, dust, and oil, and can withstand certain mechanical impacts.

[0034] The assembly, installation, and workflow of the above-mentioned device are as follows: First, install the bearing into the bearing housing, then pass the drive shaft through the bearing. Weld or secure the flange to one end of the drive shaft. Secure the bearing housing to the predetermined position on the encoder bracket. Secure the encoder to the other end of the encoder bracket. Finally, connect the drive shaft to the encoder shaft using a coupling.

[0035] The assembled device is hoisted to the side of the crane trolley, and the end caps of the target wheels are removed. The flange of the device is aligned with the end face of the wheel axle and secured with high-strength bolts to ensure coaxiality. Then, the encoder bracket is firmly fixed to the end beam of the trolley or the trolley frame by welding or bolting.

[0036] Lead the encoder's signal cable through a sealed connector and connect it to the I / O module of the safety monitoring system located in the driver's cab or electrical room. Finally, install and secure the protective cover.

[0037] like Figure 2As shown, the application method of the above-mentioned device is as follows: This embodiment not only provides a highly reliable measuring device, but also a matching intelligent measuring method including dynamic self-calibration. This method is executed by the safety monitoring system of the lifting equipment (typically a PLC or an industrial control computer with embedded algorithms), and the specific steps are as follows: Step 1: Establish linkage relationships This step is completed once the device is installed. Through the installation method described above, the flange of the drive shaft and the end face of the wheel axle of the trolley are rigidly and coaxially fixedly connected. This ensures that for every rotation of the wheel, the drive shaft also rotates precisely one rotation, with no change in the transmission ratio or slippage error between them. This is the physical basis and prerequisite for all subsequent precise calculations.

[0038] Step 2: Implement signal acquisition When the crane operator moves the trolley, the trolley wheels rotate, driving the drive shaft to rotate synchronously via the flange. Since the encoder housing is fixed to the stationary trolley end beam by the encoder bracket, the encoder's input shaft rotates along with the drive shaft. The encoder's internal photoelectric conversion system or magnetic induction system converts the detected rotation angle and number of revolutions into a series of digital electrical signals (e.g., Gray code data streams using the SSI protocol) in real time. These signals represent the most original and accurate rotation information.

[0039] Step 3: Complete data transmission and processing The electrical signals generated by the encoder are transmitted in real time to the security monitoring system via shielded cables. Upon receiving the data, the system does not use a simple, unchanging conversion, but instead executes an advanced algorithm that includes dynamic self-calibration capabilities, as detailed below: Step 3.1: Parameter Initialization and Routine Calculations Initialization: When the system is first put into use, several initial parameters need to be preset in the system memory.

[0040] Initial wheel diameter D0: For example, according to the design drawings, the initial diameter of the wheel is 500mm.

[0041] Encoder resolution R: For example, the selected encoder resolution is 4096P / R.

[0042] Initial pulse-distance conversion coefficient K0: This coefficient represents the distance the wheel travels on the track for each pulse output by the encoder (or the smallest unit of position change). Its calculation formula is: K0=(π*D0) / R. Substituting the values: K0=(3.14159*500mm) / 4096≈0.3835mm / pulse. This K0 is stored as the initial calculation basis.

[0043] During daily operations, the safety monitoring system continuously receives pulse counts (or position data) P from the encoder. The system calculates and displays the trolley's travel distance S in real time using the following formula: S = P*K0. This calculation is a conventional open-loop calculation mode before calibration.

[0044] Step 3.2: Establish calibration benchmarks To achieve self-calibration, at least two calibration reference points, namely reference point A and reference point B, need to be set on the fixed track on which the lifting equipment operates.

[0045] There are several ways to implement reference points. For example, high-precision laser rangefinders, fixed RFID tag readers, or simple mechanical travel limit switches can be installed at specific locations next to the track. These sensors can send a precise trigger signal to the safety monitoring system when the vehicle passes their location.

[0046] After installation, a high-precision measuring instrument such as a laser theodolite or total station is used to accurately measure the physical distance Lref between reference point A and reference point B. For example, Lref is measured to be 100.000 meters. This precise and unquestionable physical distance value is stored as the "standard answer" in the non-volatile storage area of ​​the security monitoring system.

[0047] Step 3.3: Perform dynamic calibration The safety monitoring system is programmed to automatically trigger a calibration process when it detects that the trolley has traveled completely between two calibration reference points. For example, after receiving a trigger signal from reference point A, the system begins accumulating the encoder pulse count until it receives a trigger signal from reference point B, at which point it stops accumulating. During this calibration cycle, the system accurately records the total number of encoder pulses output from point A to point B, denoted as Pcal. Assuming that after a period of operation, the wheels have experienced some wear, the total number of pulses recorded is Pcal = 261,530 pulses.

[0048] Step 3.4: Update conversion coefficients After acquiring the key data points Lref and Pcal, the system immediately performs the following calculation to derive a new conversion coefficient Knew that accurately reflects the actual diameter of the wheel: Knew = Lref / Pcal. Substituting the values: Knew = 100,000mm / 261,530pulses ≈ 0.3824mm / pulse. It can be seen that the new coefficient Knew (0.3824) is smaller than the initial coefficient K0 (0.3835). This accurately reflects that due to wheel wear causing a smaller circumference, more pulses are now required to travel the same distance. Essentially, this calculation process uses a "known actual distance" to reverse-calibrate the "distance represented by a unit pulse," thus cleverly compensating for the variable of wheel wear.

[0049] Step 3.5: Application and Iteration After calculating Knew, the system immediately replaces the old conversion coefficient K0 (or the old Knew obtained from the last calibration) with this new Knew in its internal program. From then on, all real-time calculations of the trolley's travel will be based on this latest and most accurate Knew: Snew = P * Knew. Furthermore, the calibration process is not a one-time event but can be continuously, automatically, and repeatedly executed. The system can be set to: periodic calibration, for example, automatically perform a calibration when the equipment completes its first round trip between points A and B each day; on-demand calibration, where operators can manually trigger a calibration process via HMI (Human-Machine Interface) whenever needed; and deviation monitoring calibration, where the system can continuously monitor the rate of change of the K value. If it finds that the change in a calculated Knew exceeds a threshold compared to the previous value, it can issue a warning message to maintenance personnel: "Severe wheel wear, please check."

[0050] Through the above steps, this embodiment upgrades a traditional open-loop measurement system into a closed-loop intelligent measurement system with self-learning, self-adaptation, and self-correction capabilities. It no longer relies on any theoretical parameters but uses a fixed physical distance as a benchmark to periodically "calibrate" itself. This fundamentally solves the problem of long-term cumulative errors caused by wheel wear, ensuring that the stroke measurement results maintain extremely high accuracy and reliability throughout the entire service life of the lifting equipment.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for measuring the stroke of a crane trolley, characterized in that, include: A drive shaft, one end of which has a flange for connection, is coaxially fixedly connected to the axle end face of the crane wheel and rotates synchronously with the crane wheel; an encoder, the input shaft of which is connected to the other end of the drive shaft for acquiring rotation data of the drive shaft and transmitting the rotation data to a safety monitoring system to calculate the travel distance; and an encoder bracket, which fixes the encoder housing to a non-rotating part of the crane to keep the encoder housing stationary when the drive shaft rotates.

2. The crane trolley stroke measuring device according to claim 1, characterized in that, The flange of the drive shaft is provided with multiple through holes, and bolts are used to pass through the through holes to fix the flange to the end cover of the wheel axle of the trolley.

3. The crane trolley stroke measuring device according to claim 2, characterized in that, The bolts are fixed through the existing bolt holes on the end cover to ensure the coaxiality of the drive shaft and the wheel axle of the trolley.

4. The crane trolley stroke measuring device according to claim 3, characterized in that, A coupling is provided between the drive shaft and the input shaft of the encoder for transmitting rotation.

5. The crane trolley stroke measuring device according to claim 4, characterized in that, The coupling is a flexible coupling used to compensate for radial, axial, and angular alignment errors that occur between the drive shaft and the encoder input shaft during installation.

6. The crane trolley stroke measuring device according to claim 5, characterized in that, The encoder bracket is a rigid metal plate structure, which includes a mounting part for mounting and fixing the encoder, and a fixing part for connecting the bracket itself to the non-rotating part of the lifting equipment.

7. The crane trolley stroke measuring device according to claim 6, characterized in that, The encoder bracket is fixed to the trolley end beam of the lifting equipment.

8. The crane trolley stroke measuring device according to claim 7, characterized in that, The end cap of the large vehicle wheel axle has a central through hole, through which the drive shaft passes and is connected to the encoder.

9. The crane trolley stroke measuring device according to any one of claims 1-8, characterized in that, The encoder is an absolute encoder.

10. A method for applying a crane trolley stroke measuring device, wherein the device is applied to the crane trolley stroke measuring device according to any one of claims 1-9, characterized in that, The steps of this method include: The flange of the drive shaft is coaxially fixedly connected to the end face of the wheel axle of the crane wheel, so that the drive shaft can rotate synchronously with the rotation of the crane wheel. The encoder collects rotational data of the drive shaft. During the data collection process, the encoder housing is fixed to the non-rotating parts of the lifting equipment by the encoder bracket to keep it stationary. The rotation data collected by the encoder is transmitted to the safety monitoring system, which then calculates the actual travel distance of the crane trolley based on the rotation data. The specific steps are as follows: The safety monitoring system has a preset initial pulse-distance conversion coefficient, which is based on the initial design diameter of the vehicle wheel. The safety monitoring system receives the number of pulses generated by the encoder and calculates the travel distance in real time by multiplying the number of pulses by the initial pulse-distance conversion coefficient. At least two calibration reference points are set at fixed positions on the track where the lifting equipment is running, and the actual physical distance between the two calibration reference points is stored in the safety monitoring system. When the safety monitoring system detects that the crane trolley is running completely between the two calibration reference points, a calibration process is triggered: the safety monitoring system records the total number of pulses output by the stroke encoder during this calibration. The safety monitoring system uses the actual physical distance of this calibration trip and the total number of pulses recorded to divide the actual physical distance by the total number of pulses to obtain the pulse-distance conversion coefficient that reflects the current wheel condition. The safety monitoring system replaces the initial pulse-distance conversion coefficient with the calculated pulse-distance conversion coefficient, and uses this as the benchmark for all travel distance calculations. It repeats the process according to a preset cycle to achieve continuous dynamic compensation for wheel wear.

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