Hydraulic Lifting Mechanisms for the Erection Equipment

The steel gate based on the principle of hydraulic lifting mechanism has been widely used in urban water ecological construction, but the retaining height of this kind of gate is mostly l-5m at present. With the development of water conservancy engineering and the deepening of the application research of steel gate, the retaining height gradually grows to 6-8m. However, at present, there are few researches on hydraulic lifting mechanism in the case of large retaining height. In this paper, Inventor is used to firstly establish three-dimensional visual entity models of the direct push type, Booster type and Maleli type hydraulic lifting mechanism. Then, the changing rules and relations among hydraulic cylinder diameter, stroke and stability safety factor of the three hydraulic lifting mechanisms are calculated and analyzed by changing the constraint conditions in the case of large retaining height (4m, 5m, 6m, 7m, 8m) and different opening and closing angles. It is aimed at providing a scientific basis for the optimization of hydraulic lifting mechanism of steel gate under the condition of large retaining height.

Based on the analysis of characteristics and Application requirements, one type of micro pure electric garbage transfer vehicle was designed. The power layout program, chassis layout and hydraulic lifting mechanism were researched to meet the driving safety need and automobile ride. The McPherson independent front suspension and the coil spring integral rear suspension were selected as the suspension program. The type of motor front and front drive was the arrangement of power system. The ladder frame chassis was selected for its high strength and low cost and the finite element analysis of frame was executed to verify the strength. The lifting mechanism was the key of the vehicle, one integrated hydraulic lifting mechanism was selected and the lifting time and angle and cylinder diameter were calculated. The tests confirm the sample vehicle being of reliable design and good performance.

With the continuous improvement of the level of intelligence in the construction machinery industry, as one of the core technologies in the hydraulic lifting and rotating system, the lifting transmission control system has become a key factor in determining the performance of the elevator. As a hydraulic lifting machine with high protection level and powerful functions, the mechanical transmission controller has been recognized by the market. This study is based on the design of lifting machinery transmission control of hydraulic lifting and rotating system and studies the lifting mechanism transmission system in the hydraulic lifting and rotating system required for engineering operation. According to the functional characteristics of the transmission controller of the lifting mechanism, the control system scheme is designed. On this basis, the system design of the lift machinery transmission control and, according to this design, the functions of driving speed control and transmission mode switching are studied. Starting from the movement mechanism of hydraulic continuous lifting technology, this research carried out the principle design of mechanical transmission control, related calculations, selection of hydraulic components, corresponding simulations, structural design of mechanical transmission, and tests of hydraulic power systems. Finally, the control system was verified through simulation experiments, and technical difficulties such as the liquid supply mode of the large-flow system, the selection of standby working conditions, and the reliability and safety design were solved. It can be seen from the simulation results that, as the displacement ratio increases, the system efficiency increases, reaching more than 70%. When the valve opening reaches 20° when the valve port is closed, the efficiency of the power control valve reaches 95%. It can be seen that the control system established in this study has more advantages in power and economy. The transmission control system of hoisting machinery designed in this study can give greater play to its transmission efficiency and significantly reduce the working time and intensity of the operator.

For the correct operation of hydraulic lifting mechanisms of the installation equipment of rocket and space complexes, it is necessary to ensure the synchronous movement of the rods of hydraulic power cylinders operating in parallel when performing working operations. Therefore, the urgent task is to develop synchronization systems that, along with ensuring the consistency of travel speeds, also provide the consistency of the mutual position of hydraulic cylinder rods. To solve this problem, we introduce a new approach which makes use of indirect methods for determining the working stroke of hydraulic power cylinders according to the results of measuring the angular or linear coordinates of the power elements of the mechanism. The first method is based on measuring the angular coordinates of the power elements of the lifting mechanism using angular displacement sensors - angular encoders. As for the second method, it relies on measuring the stroke of an additional link of variable length by means of magnetostrictive and cable linear position sensors. The paper briefly describes the device and the principle of operation of the sensors, and gives recommendations for the construction of measuring transducers as part of the lifting mechanism of the installation equipment. The new approach to solving the problem of controlling the stroke of hydraulic power cylinders in lifting mechanisms can be used in the development of advanced installation equipment for launch vehicles of heavy and superheavy classes.

A continuous variable valve lift (VVL) mechanism for a diesel engine is proposed in this research. The hydraulic mechanism, which consists of a driving plunger, a driven plunger, a hydraulic cylinder, and a hydraulic oil tank, is the key part of the VVL mechanism. Simulation is conducted to study the relationship between maximum valve lift and rotation angle of driving plunger. Calculation results indicate that the maximum valve lift decreases with increasing rotation angle. A prototype was manufactured and successfully tested in a single-cylinder diesel engine. The experiments, which were conducted at different rotation angles of the driving plunger, validate the accuracy of the calculation results. The difference between experimental valve lift curve and cam lift curve is considered the result of oil leakage. Rotating the driving plunger is an effective method to regulate valve lift. Working stability of the VVL mechanism is validated through a multi-cycle operation. Experimental results indicate that the VVL mechanism is effective and reliable for realizing continuous VVL in engines.

At present, due to the high labor intensity, low level of mechanization, automation, and intelligence in garbage collection, the existing garbage collection mode, garbage collection and transportation facilities and technologies are no longer able to quickly and timely meet the increasing demand for garbage. In response to the problems of structural instability, garbage leakage, and damage to garbage bins in the mechanical arms of current garbage trucks, this article designs a hydraulic rod series driven lifting flipping mechanism to address these issues; The dual hydraulic rod lifting mechanism and distance compensation mechanism are used to achieve multifunctional collection and dumping of garbage bins, solving the problem of traditional garbage trucks relying on manual pulling or human eye positioning of the distance between the vehicle and the bin for lifting and dumping, and the easy occurrence of slipping during the dumping process, thus improving the efficiency and automation level of garbage collection and dumping. The dual hydraulic lifting structure improves the stability of the gripping work and can significantly increase the weight of the garbage bin that can be gripped. The distance compensation mechanism can improve the accuracy of the robotic arm gripping and reduce the difficulty of operation. Different clamping forces are set according to the weight of different trash cans, and the structural rationality and functional feasibility of the robotic arm are verified through experiments, solving the problem of trash cans easily falling off or collapsing during the clamping and dumping process. Design the control system for the robotic arm of the garbage truck and conduct dumping experiments on the entire machine to meet different usage requirements under various working conditions.

The leveling process for the hydraulic lifting mechanism of the bricklaying robot is complicated. The article presents the designing process and method of controlling a four-cylinder electro-hydraulic (EH) servo drives system. As a part of the research, a mathematical model was established and the process of leveling a mobile support platform of the bricklaying robot was optimized. A kinematic analysis of the lifting mechanism was carried out. The mathematical model of the hydraulic system was presented. The work scheme was designed on the base of the strategy of leveling and planning the displacement trajectory of individual EH servo drive. The designed control system takes into account not only position errors for individual drive axis, but also synchronization errors with neighboring axes. The synchronization function for the control system, which takes into account the positioning errors of individual drive axis, was specified.

This paper is made from a certain type of truck crane hydraulic lifting mechanism system as an object, then the second lifting working condition is analyzed. With AMESim, according to the hydraulic system diagram building lifting mechanism hydraulic system simulation model, hereby corresponding simulation conditions is set and the effects of secondary slide response on input signal, hoisting load, discharge and speed of pump, fluid resistance of one-way throttle is studied. This research on truck crane hoisting mechanism hydraulic system provides the theory basis for the design improvement, the relevant research methods and means have reference on the research of other engineering machinery hydraulic system working characteristics.

This article discusses the main structures and operating principles of railway cranes, as well as their common faults, and offers an analysis of fault reports related to their use. The key elements of crane constructions, including lifting mechanisms, undercarriage, booms, control systems, hydraulic devices, and safety systems, are described. The most common faults identified during operation, such as wear of structural elements, faults in control systems and hydraulic mechanisms, as well as damage due to overloading or prolonged use, are given special attention. Based on the analysis of fault reports, the main causes of failures are identified. The article highlights the importance of preventive measures, including regular maintenance and adherence to safety guidelines by operators. Collecting fault information and compiling statistics plays a crucial role and is significantly beneficial for designers, operational specialists, as well as developers and reviewers of railway crane safety regulations.

“How should I apply this information?” Canchild’s motor growth study has shown that young children with cerebral palsy (CP) achieve their motor milestones at an accelerated rate compared with that of older children with CP.1 From these data, it seems crucial to provide intensive physical therapy intervention at a young age to children with CP. One of these interventions is the use of locomotor treadmill training (LTT) in an attempt to maximize walking independence, walking endurance, and gait speed. LTT differs from body weight–supported treadmill training in that LTT uses as little weight support as possible. LTT fits in current rehabilitation opinions for providing task-specific training with multiple repetitions to children with CP. LTT has been studied in children with CP, both ambulatory and nonambulatory. Despite encouraging results, relatively few studies have been performed in the younger age group. To fill this gap in the literature, the effects of an intensive LTT intervention were examined in children younger than 4 years with different types and severity of CP on functional standing and walking skills. Young children with CP were enabled to take independent steps on the treadmill with as little support or facilitation as possible. The possible adverse effects of LTT such as excessive fatigue or other forms of discomfort were also studied. The study provided preliminary evidence that intensive LTT in this small sample of preschoolers with CP improved gross motor function, maximum and self-selected walking speed, and walking endurance, with no harmful side effects. “What should I be mindful about in applying this information?” The findings of this study add to the body of knowledge that functional standing and walking skills can be improved by intensive treadmill training in preschool children with CP. This study is important in that it describes an intensive physical therapy program for young children, which can be easily adapted to the child’s level of skill. The next 3 factors were beyond the scope of this study, but these should be considered when applying the results. First, it is crucial that preschoolers develop competence in movement skills, which are the basis for more complex movement tasks later in life. Because locomotor training for preschoolers with CP is designed to provide task-specific training, it can be questioned whether intensive walking is the best intervention for all children with CP. For children classified under Gross Motor Function Classification System (GMFCS) levels IV and V, intensive therapy on a bicycle or wheelchair seems to be more task specific. At an older age, these children may continue to walk for only short distances with physical assistance at home, relying more on wheeled mobility. Second, the authors note that for preschoolers a program longer than 4 weeks might be necessary to make significant physiological changes in endurance. A minimum of 6 weeks with 3 training sessions per week seems to be more appropriate and might lead to better results. Third, the authors also note that intensive LTT requires a large time commitment for parents and children and is difficult to continue outside a research setting. They suggest that home-based treadmill training might be beneficial and cost-effective for this population. However, a weight-support harness system with hydraulic lifting mechanism is expensive, not easy to use, and needs supervision. Moreover, home treadmills, which have been growing steadily in popularity, pose a specific hazard to preschoolers, and safety is always a concern while supervision is necessary. Additional home treadmill safety guidelines must be established. Although long-term effects of intensive physical training at a young age are not known, one can only assume that an early introduction to a lifestyle that includes intensive exercise would be beneficial for the future health and physical activity of children with CP. The pediatric physical therapist is a key player in educating parents about their role in giving their children a healthy start. An intensive intervention, such as LTT, early in life may help boost levels of physical activity, which may have a more influential impact on obesity and other health risks later in life. Olaf Verschuren, PT, PhD, PCS Centre of Excellence, Rehabilitation Center ‘de Hoogstraat’, Utrecht, The Netherlands Paul J.M. Helders, PT, PhD, MSc, PCS Faculty of Medicine, Division of Pediatrics, Utrecht University, Child Development and Exercise Center, University Medical Center and Children’s Hospital, Utrecht, The Netherlands

The synchronous system of hydraulic lifting mechanism always could not get enough synchronous precision because of load imbalance and two-cylinder size discrepancies. The paper uses MATLAB/simulink toolbox to create simulative model of the system, and applies fuzzy control to improve synchronous precision. Simulative results show that the system adopted the fuzzy control enables further improved synchronous precision to 0.09mm, and the slave cylinder speed can follow the active cylinder speed well. The average peak speed is 20.5mm/s and 20mm/s. So for this synchronous system it has a good control effect.

Simulation Analysis of Hydraulic Lifting Mechanism of a Forklift

This article discusses the dynamics of power processes upon motion of bascule metal structures peculiar for many lifting heavy-duty mechanisms. Due to the forces of inertia, during the acceleration of the mechanism with a load, fluctuations in power parameters occur: efforts; stress; pressures that can lead to the destruction of the metal structures of machines. Due to high alternating load oscillations, the working capacity of machinery decreases about 3 times, herewith, this problem is traced for machinery in various industries. Using the motion of large-tonnage span of bascule bridge as the example, at the design stage it is proposed to apply simulation modeling in order to determine optimum law of drive control, in particular: the law of variation of flow rate in fluid power systems. The article presents the results of simulation of hydraulic lifting mechanisms of a single-wing bascule bridge. Two basic algorithms of proportional control are considered: by the form of the function in the form of a trapezoid and by the form of the cosine function. The results indicate the possibility of significantly reducing the amplitude of fluctuations in load parameters during acceleration of mechanisms and, thereby, to increase the service life of heavy machines. To achieve such results, it is recommended to change the existing algorithms for automatic control of the speed of the mechanisms of heavy machines. Despite the fact that this issue has been studied quite well in cybernetics, it still remains relevant in applied technical specialties, in the design of modern heavy machines. In project organizations, along with constructive design methods, digital, computational design methods should be actively developed.

Vegetation root water uptake is one of the most central water transport processes along the soil-vegetation-atmosphere interface particularly in (semi-)arid ecosystems. The identification and quantification of root activities and water uptake patterns of arid vegetation remain challenging. This paper aims at the quantitative examination of water uptake behaviors of Nitraria, a prevalent desert species in arid environments, during the growth phase via a multivariate linear mixed model based on water stable isotopes, with a main focus on the time interval from a precipitation pulse. The observations indicate that the precipitation events exert periodic significant pulse-effects on vegetation water uptake through direct absorption (contribution of almost 75%) and activation of deep root activity at a certain depth. While in most occasions without rainfall, Nitraria relies on its extremely extensive shallow roots in surface-near lateral zone (contribution of about 60%) to extract massive soil as well as the hydraulic lifting mechanism to survive drought. Achievements would be beneficial to enhancing the understanding of entangled water transport processes and eco-hydrological feedbacks along soil-vegetation interface in arid ecosystems and contribute to a scientific allocation to water resources with the consideration of ecological protection.

A mechanical parking system is an important parking equipment that can improve the utilization rate of urban space. In China, the lift-sliding mechanical parking system is the most widely used. Among many types of drives, the hydraulic pump-hydraulic cylinder type has advantages such as convenient system integration and expansion, energy saving, etc. The system is prone to vibration and pressure shock during operation. This paper focuses on the causes of vibration and hydraulic impact, constructs a simulation model, and analyzes the causes of vibration and hydraulic impact through simulation results, guiding equipment optimization.