Clamping Mechanism Research Articles

Optimum Design of Profiled Root–Trimming Device for Pull–Cut Harvester of Leading–Drawing–Cutting Type

In this study, a leading–drawing–cutting–type profiled root–trimming device was designed to address the problems of high impurity and damage rates that occur with the operation of a pull–cut garlic harvester. The main components of the designed device include a pull–clamp mechanism, roll–pulling mechanism, root–trimming knife mechanism, lifter, gearbox, universal drive shaft, motor, and frame that, together, can complete the root–trimming operation for a pull–cut garlic harvester. An orthogonal regression test was carried out by taking the roller diameter, the roller inclination angle, the knife rotation speed, and the working speed as factors and by taking the impurity rate and the damage rate as indices. The results of the orthogonal regression test showed that the impurity rate was most strongly affected by the roller diameter, followed by the knife rotation speed, the working speed, and the roller inclination angle. Meanwhile, the damage rate was most strongly affected by the knife rotation speed, followed by the roller diameter, the working speed, and the roller inclination angle. The regression analysis showed that when the roller diameter was 100 mm, the roller inclination angle was 25°, the knife rotation speed was 200 r·min−1, and the working speed was 1.22 km·h−1, the comprehensive trimming quality reached its maximum value of 97.82%. The verification result of the parallel test gave a value of 97.52%, which was mainly affected by the irregular sizes of the bulbs, but it showed no significant difference from the regression analysis results. The tests verified that the profiled root–trimming device could be applied to develop the technology of garlic pull–cut harvesters.

Design and Test of Seedling-Picking Mechanism of Fully Automatic Transplanting Machine

The seedling retrieval mechanism is a crucial component of fully automatic transplanting machines, significantly influencing the quality, reliability, and efficiency of the transplanting process. Nonetheless, the existing seedling retrieval mechanisms in current transplanting machines exhibit several deficiencies, including substantial damage to seedlings and inadequate retrieval accuracy. To overcome these challenges, we propose an integrated approach combining pneumatic and mechanical techniques to further improve performance. By employing a lower thimble elevation and clamping mechanism, alongside a mathematical model based on the seedling removal process, this method ensures precise seedling extraction and minimizes damage to the root system and substrate. The novelty of this study lies in its ability to reduce the adhesion between seedlings and the holes of the plug plate, thereby minimizing non-destructive extraction of the seedlings and preserving the integrity of the matrix, which is essential for ensuring healthy seedling growth. Moreover, the optimization of the seedling retrieval trajectory enhances the accuracy of the seedling retrieval mechanism while also meeting the requisite speed requirements. Experimental results indicate that at a rate of 72 seedlings per minute, the extraction success rate reached 94.90%, and the casting success rate was 98.53%. The seedling injury rate was only 1.95%, resulting in an overall success rate of 91.69%. These findings confirm that the device meets operational efficiency requirements and delivers effective performance.

Characterization of Hydraulic Spool Clamping Triggered by Solid Particles Based on Mechanical Model and Experiment Research

Hydraulic spool valves may clamp under the action of sensitive particles when working in hydraulic oils that contain solid particles, which will then bring about a devastating detriment to the machines. According to the failure statistics of hydraulic systems organized by ISO, more than 80% of the operational failures of hydraulic systems are caused by fluid contamination, and particulate contamination is the most important factor causing spool valve stagnation. In this paper, we considered various factors, including the material, size, and concentration of particles and the spool postures, and built a systematic spool clamping mechanical model. A device was designed to measure the spool valve friction under the action of particles. The influence of particle material, concentration, and size on the friction force of spool valves was investigated. By experiments, we measured the spool clamping force under the action of each single factor and then fitted the datum quantity of spool clamping force and the empirical equation of pulsating quantity. The study results demonstrate three types of non-ideal postures of spools in a valve hole, which are off-center, tilting, and off-center with tilting. Those three postures can engender clamping risk zones with different ranges inside the clearance between spool valves, increasing the risk of spool clamping. The kind of particles is found to have a certain but limited impact on the spool clamping force. Usually, particles with a higher elastic modulus can trigger a larger spool clamping force, which is in line with the theoretical equation. Within a certain range, the probability density distribution of particle size tallies with the normal distribution function, where the “sensitive particles” take up 0.7–1 of the clearance between spool valves. A higher particle volume fraction in oils means a greater number of sensitive particles and a larger spool clamping force. For the particles of a similar size with the clearance between spool valves, when their volume concentration tops over the “sensitive concentration”, namely 5%, the risk of spool clamping rises in a drastic manner. This study provides a theoretical reference and an empirical equation for the mechanism of spool clamping under the action of particles, as well as a definite quantitative indicator for the prediction and estimation of spool clamping which is of positive significance for the study of the predictive maintenance of hydraulic equipment.

Electroacupuncture alleviates sciatic nerve injury and inhibits autophagy in rats.

Sciatic nerve injury is a common form of peripheral nerve injury (PNI). It has been suggested that electroacupuncture (EA) stimulation at GB30 and ST36 can improve nerve dysfunction post-PNI. Autophagy is an important factor in the regeneration of sciatic nerves and recovery of motor function. Therefore, we investigated the biological effects of EA and examined whether these were mediated by autophagy in sciatic nerve injury. Mechanical clamping of the sciatic nerve in Sprague-Dawley rats was performed to establish an experimental model of sciatic nerve injury. EA stimulation was administered once daily for 15 min for seven consecutive days beginning 1 week after successful modeling. The recovery of sciatic nerve function was examined via the sciatic functional index (SFI) test. Morphometric analysis was conducted by staining nerve samples with toluidine blue. Autophagy-associated protein levels were measured via Western blotting. EA stimulation at GB30 and ST36 significantly increased the number of myelinated fibers, axonal and fiber diameters, and the thickness of the myelin sheath in our rat model of sciatic nerve injury. In addition, EA stimulation greatly facilitated nerve regeneration following sciatic nerve injury. Moreover, sciatic nerve injury-induced autophagy was inhibited by EA stimulation. EA facilitates recovery of injured sciatic nerves and inhibits autophagy in a rat model.

Interface characteristics and performance of additively manufactured steel-titanium bimetals prepared through composition gradient layers

In this study, laser-directed energy deposition (LDED), a powder-feeding laser additive manufacturing technique, was utilized to fabricate bimetals comprising high-strength steel (HSS) and Ti6Al4V (TC4). Through meticulous compositional control, four distinct regions (labeled Areas 1 through 4) comprising Fe-Ti intermetallics with varying sizes and morphologies were obtained at the LDEDed HSS/TC4 interface. These zones exhibited thicknesses of approximately 190 μm, 210 μm, 525 μm, and 205 μm, respectively. The effect of these intermetallics on the performance of LDEDed HSS/TC4 bimetals was investigated. The results indicated that most Fe-Ti intermetallics, characterized by reticular/granular morphologies or fine precipitates, were dispersed at the bonded interfaces (Areas 1, 3, 4). Nevertheless, irregular and long-striped C14_Laves phases were observed in Area 2, indicating the presence of a pure Fe2Ti region. Performance testing revealed that fractures predominantly occurred within a hard and brittle Fe2Ti region (Hardness: 891.5HV) during mechanical grinding or tensile clamping, highlighting the formidable challenge of achieving high-quality LDEDed HSS/TC4 bimetals through a component-regulated building strategy. The difficulty arises from the high Fe content in HSS and high Ti content in TC4, resulting in the formation of a pure Fe2Ti region at the interface. Thermodynamic calculations suggest that the composition-gradient-layer strategy may not be optimal for the integrated laser additive manufacturing of HSS and TC4. These findings provide valuable insights into the design of steel-titanium functional gradient materials and other multi-material components.

Operando electron spin probes for the study of battery processes

Operando electron spin probes, namely magnetometry and electron paramagnetic resonance (EPR), provide real-time insights into the electrochemical processes occurring in battery materials and devices. In this work, we describe the design criteria and outline the development of operando magnetometry and EPR electrochemical cells. Notably, we show that a clamping mechanism, or springs, are needed to achieve sufficient compression of the battery stack and an electrochemical performance on par with that of a standard Swagelok-type cell. The tandem use of operando EPR and magnetometry allows us to identify five distinct and reversible redox processes taking place on charge and discharge of the intercalation-type LiNi0.5Mn0.5O2 Li-ion cathode. While redox processes in conversion-type electrodes are notoriously difficult to investigate using standard characterization methods (e.g. X-ray based) and/or post mortem analysis, due to the formation of poorly crystalline and metastable reaction intermediates and products during cycling, we show that operando magnetometry provides unique insight into the kinetics and reversibility of Fe nanoparticle formation in the Na3FeF6 electrode for Na-based batteries. Step increases in the cell magnetization upon extended cycling indicate the build-up of Fe nanoparticles in the system, hinting at only partially reversible charge–discharge processes. The broad applicability of the tools developed herein to a range of electrode chemistries and structures, from intercalation to conversion electrodes, and from crystalline to amorphous systems, makes them particularly promising for the development of electrochemical energy storage technologies and beyond.

Discovery of a neuropeptide that acts as an autotomy-promoting factor

One of the most remarkable adaptations to survive attacks from predators is to detach an appendage-a process known as autotomy. This occurs in a variety of animals, including lizards (tail), crabs (legs), and starfish (arms). There has been extensive investigation of the evolution, ecology, and biomechanical impact of autotomy,1,2,3 but little is known about neural mechanisms controlling autotomy in animals. However, evidence for the existence of a peptide that acts as an autotomy-promoting factor in starfish has been reported.4 While investigating invivo effects of a sulfakinin/cholecystokinin-type neuropeptide (ArSK/CCK1) in the starfish Asterias rubens,5,6 we observed that this peptide triggered arm autotomy in some animals. Furthermore, when injection of ArSK/CCK1 was combined with mechanical clamping of an arm, autotomy of the clamped arm occurred in 85% of animals tested, with 46% also autotomizing one or more other arms. In contrast, no autotomy was observed in clamped animals that were injected with water (control). To examine the physiological relevance of these findings, we analyzed expression of ArSK/CCK1 in the autotomy plane, a specialized region at the base of the arms in A.rubens.7,8 In accordance with its invivo effects, nerve fibers expressing ArSK/CCK1 were revealed in the tourniquet muscle, a band of muscle that mediates constriction of the arm during and after autotomy. We conclude that ArSK/CCK1 acts as an autotomy-promoting factor in starfish and as such it is the first neuropeptide to be identified as a regulator of autotomy in animals.

Experiment and analysis of physical, mechanical, and viscoelastic properties of the roots and stalks of green leafy vegetables.

Green leafy vegetables are an essential component of Chinese leafy vegetables. Due to their crisp stems and tender leaves, orderly harvester generally causes significant mechanical clamping damage. The physical and mechanical properties of green leafy vegetables are one of the important basis to design the orderly harvester. At the same time, they provide important parameters for the simulation and optimization of harvester. So, this paper measured the physical characteristic parameters of roots and stems of green leafy vegetables. Then, based on the TMS-Pro texture analyzer, the elasticity modulus of the roots and stems of green leafy vegetables were measured. The static friction coefficient, dynamic friction coefficient, and restitution coefficient of green leafy vegetables root-root, stem-stem, root-steel, and stem-steel were measured separately using a combination method of inclined plane and high-speed photography. Uniaxial compression creep experiments were carried out on whole and single leaf of green leafy vegetables using the TA.XT plus C universal testing machine. The constitutive equation of the four-element Burgers model was used to fit the deformation curve of the sample with time during the constant-pressure loading stage. The fitting determination coefficients R2 were all higher than 0.996, which verified the reasonable validity of the selected model. The above experimental results provide a parameter basis and theoretical support for the design and discrete element simulation optimization of orderly harvester critical components of green leafy vegetables.

Design and Research of Intelligent Fixture for Drawing Machine

Tensile machine is a very sophisticated test equipment, which can test the mechanical properties of some materials. In the drawing machine, the clamping device is to prevent the relative displacement and vibration phenomenon in the process of tensile test. The clamping device is the most important part of the structure of the test machine, and the main task of the clamping device is to control the degree of freedom of the specimen needs to be clamped, so as to further add loads to the various specimens to be held, and finally complete the mechanical property test of the material. But at present, the existing fixture mechanism is mainly hydraulic, pneumatic, mechanical fixture. At present, the existing mechanical fixture still has bending stress during the clamping process, which will affect the accuracy of the experiment. Therefore, a clamping mechanism with adjustable clamping force and flat pushing is designed. An electric control type fixture mechanism is very rare, so in this paper, an electrically controlled fixture is designed on this basis. The main contents are as follows: (1) On the basis of the existing fixture types, the working mode of the fixture is studied, and the working principle related to the fixture is mastered. (2) The main components of the fixture mechanism are analysed, the design scheme is determined, and the selection of the components of the drive part and the selection of the related components within the fixture mechanism is completed. ( 3) The force analysis of the main body of the fixture is carried out by using theoretical mechanics knowledge, and the relevant calculations are completed. The solid modeling of the whole mechanism is completed by using SolidWorks. The force analysis of key parts is carried out by using ANSYS software, and the correctness and safety of material selection and design are verified. The main parts of the fixture mechanism to complete the corresponding force analysis, and the theoretical calculation results are compared and verified, and finally realize the electric control of the fixture mechanism and complete the design of the fixture mechanism.

A Single-Clamp Inchworm Actuator with Two Piezoelectric Stacks.

Inchworm piezoelectric actuators have attracted much attention in the field of precision positioning due to the advantages of a large stroke, high output force, and high resolution. However, traditional inchworm piezoelectric actuators use two sets of clamps and a set of drive structures to achieve stepping motion, which generally requires at least three piezoelectric stacks, resulting in a complex structure and the control system. Several methodologies have been advanced to minimize the utilization of piezoelectric stacks. However, there still exists the issue of excessive volume. Therefore, an inchworm piezoelectric actuator with a single-clamp and single drive structure is proposed in the study, which provides a compact size and smaller volume. The clamping mechanism comprises two sets of clamping feet with opposite displacement, which alternate contact with the guide frame and adjustable plate to ensure that the clamping mechanism always has frictional force and accomplishes the stepping motion. The testing of the actuator's step distance, output force, and other parameters was conducted utilizing a displacement sensor. Experimental results indicate that the actuator achieved a maximum speed of 174.3 μm/s and an output force of 8.6 N when the frequency and voltage were 19 Hz and 150 V.

Direct and converse piezoelectricity of thickness tuned BCZT ceramics: toward efficient bilayered magnetoelectric devices

Here we report the effect of thickness reduction of bulk 0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Ti0.8Zr0.2)O3 (BCZT) pellet on its direct and indirect piezoelectric properties. Upon reducing the thickness to 0.3 mm, the pellet shows a very high electrostrain of ∼0.7% and piezoelectric coefficient of ∼353 pC/N which were ∼0.14% and 258 pC/N for the 1 mm thick sample. These results have been correlated with the reduction in hardness and mutual mechanical clamping between the grains due to the reduced thickness of BCZT. Due to this improved strain sensitivity, the bilayered magnetoelectric (ME) devices of BCZT with magnetostrictive CoFe1.9Bi0.1O4 (CFBO) pellet have also shown gradually improved ME coupling coefficient ( αME ) with reduced BCZT thickness ( αME = 27 and 66 mV·cm−1·Oe−1 for 1 and 0.3 mm BCZT thickness, respectively). This demonstrates the possible applicability of thickness tuned BCZT pellets for various technological purposes.

Key Technology Research and Equipment Development of Automatic Spool Feeding Device

To solve the problems of high labour intensity and low efficiency of artificial spool feeding, an automatic spool feeding device is developed. SolidWorks is used for overall structural scheme design and determination of design parameters. The kinematic equation of the chain conveyor line is established, a mathematical model is solved with MATLAB, and sprocket, and chain parameters are selected. The clamping mechanism and turnover mechanism are designed, theoretical analysis of the key structure is completed. Dynamic simulation of the chain conveyor line is carried out by ADAMS, and preliminary operational stability is determined by combining motion curves. The test prototype is developed for feeding tests and measurement of the operating parameters. The test results show that the efficiency of machine feeding is 13% higher than that of manual feeding, the average feeding time is 43% lower, the halt waiting time is 43% lower, and the operating parameters are by the theoretical design and the work is reliable. The research results can provide a reference for similar spool-feeding devices.

Mechanical clamping by inverse piezoelectric effect to improve the electromechanical coupling effect of a 1-3 PZT/P(VDF-TrFE) composite sheet

Mechanical clamping by inverse piezoelectric effect to improve the electromechanical coupling effect of a 1-3 PZT/P(VDF-TrFE) composite sheet

Research on Symmetrical Flexible Clamping Conveyor for Scallion Harvester

Aiming at the problems of low conveying efficiency, poor adaptability of conveying Scallion poles of different diameters, and little innovation of the mechanism that exist in the existing clamping conveyor device, a symmetrical flexible clamping conveyor device suitable for Scallion harvesting was innovatively designed. The design and analysis of the overall structure of the clamping conveyor, the clamping mechanism, the clamping pulley and other key mechanisms were carried out, and finally the finite element simulation analysis of the clamping conveyor was carried out, and the analysis of the deformation cloud and stress cloud showed that the designed clamping conveyor could meet the requirements of the working strength. The designed symmetric flexible clamping and conveying device can automatically adjust the clamping force according to the diameter of Scallion stalks to realize efficient and lossless clamping, which is more innovative than the existing clamping and conveying devices.

Design of Automatic Seaming Machine for Fire Air Ducts with 3D Model and Its Experiment

The fire air duct is one of the important components of the ventilation system in large buildings, which is is a unit system for ventilation and smoke exhaust. The ventilation system is a customized system with a wide range of applications and a high demand, resulting in the use of multiple sizes and specifications of fire air ducts. At the same time, fire air ducts are generally made of thin galvanized iron sheets, which have poor rigidity and are prone to deformation. For the two above-mentioned reasons, the seaming process of the fire air duct is currently mainly completed by manual tapping, resulting in low processing efficiency, high labor intensity, and high cost. Therefore, it is necessary to design an automated equipment that can complete the fire air duct seaming process. Firstly, a 3D model for automatic seaming machine for fire air ducts to demonstrate the working principle and a double head positioning and clamping mechanism is proposed to improve the pipe rigidity; Secondly, to adapt to most specifications for rectangular fire air ducts, a system was designed that utilizes the two right angle ends of the stitching edge for positioning and clamping without many special toolings. Thirdly, a set of automatic seaming prototype has been manufactured based on the above design ideas. The experimental results on the prototype show that the fire air duct automatic stitching machine can seam a fire air duct within 1 minute. Compared with manual processing, the processing efficiency is improved by more than 80%.

Research report on automatic unpacking operation of measuring instrument storage buffer area

In order to realize the automatic, digital and intelligent research and development of the key process of unpacking, this paper designs an intelligent unpacking equipment based on visualization of the makeup and unloading system, and the efficiency is seriously not matched. intelligent unpacking equipment based on visual positioning algorithm, including the main frame of the unpacking machine, the film winding device, the automatic film cutting and the film clamping. automatic film cutting and the film clamping mechanism. Based on the above design, the test simulation is carried out. In the actual work, the intelligent unpacking workstation can significantly improve the current manual unpacking work efficiency (increase efficiency > 50%), and realize the automation, digitalization and intelligence of the current manual unpacking work efficiency (increase efficiency > 50%), and realize the automation, digitalization and intelligence of the operation process in the front area of the library. In the actual work, the intelligent unpacking workstation can significantly improve the current manual unpacking work efficiency (increase efficiency > 50%, and realize the automation, digitalization and intelligence of the operation process in the front area of the library.

Development and field testing of biodegradable seedling plug-tray cutting mechanism for automated vegetable transplanter

Removing seedlings from plug-trays to transplant in the field poses transplanting shocks to the seedlings and may reduce the survival rate. Therefore, this study designed biodegradable plug-tray cutting mechanism (SPCM) that separates seedlings with plug-cells from plug-trays and eliminates a complex clamping mechanism. SPCM consists of three sub-mechanisms that align the plug-cell at the seedling discharge point to cut and separate the plug-cell from the plug-tray, allowing the seedling to fall into the transplanting hopper. The SPCM separated around 82% of the plug-cell and delivered it to the planting unit. Furthermore, the SPCM-equipped transplanter achieved a transplanting performance of 74% with pepper and cabbage seedlings, with an average field efficiency of 68%, field capacity of 0.032-0.035 ha h-1 and required 73% less labour than manual seedling transplanting. The transplanting performance was satisfactory, with most pepper seedlings (85%) transplanted with a planting angle less than 10°, and 7% of cabbage seedlings were inclined and had sufficient planting depth of 48 mm for cabbage and 53 mm for pepper. In conclusion, the SPCM is a step towards sustainable and efficient vegetable seedling transplanting. Increasing efficiency, planting accuracy, and sustainability present exciting opportunities for further research and development in the field.

A unique clamping mechanism for a cylindrical PEMFC for an enhanced performance

Polymer electrolyte membrane fuel cells with planar structures have been proven beneficial; however, cylindrical cells have higher gravimetric and volumetric power density with possible applications in aviation and portable power sources. In this study, a unique clamping mechanism for a cylindrically structured polymer electrolyte membrane fuel cell is developed to improve the performance of the cell through reduced contact resistance over the active area of the cell. The design is structurally modelled and simulated for the contact pressure distribution, followed by experimental validation of contact pressure distribution at the interface of the gas diffusion layer and current collector. The study results in a lower ohmic resistance due to the better electrical contact at the interface of gas diffusion layer and current collector using the new clamping system. The average contact pressure with the new system is observed to be 0.40 MPa, i.e. 33% higher than that of the strap clamping system. In addition, the contact resistance of the cell with new clamps is found to decrease by 18 %, thus resulting in 36 % better performance (55 mW/cm2 at 0.6 V) than that of the conventional clamping system (40 mW/cm2 at 0.6 V). Such enhancement is also attributed to more oxidant supply (12%) at the cathode current collectors due to better cell clamping design.

Dynamic analysis of aircraft towing slip-out system considering vertical wheel constraints

Abstract To analyze the vertical dynamic characteristics of the aircraft towing system under different constraints on the nose landing gear wheels of the aircraft during the towing slip-out mode, a dynamic model of the towing system considering the constraints between the clamping mechanism and the aircraft nose landing gear wheels was established based on the general towing system dynamic model. On this basis, an analysis was conducted to determine whether considering the aircraft wheel constraints affects the vertical vibration acceleration of the towing vehicle and the nose landing gear in low-speed (10 km/h) and high-speed (40 km/h) operating conditions. With the consideration of constraints at both ends of the aircraft wheels, the vertical acceleration of the towing vehicle's center of mass increased by 153% and 172% at low speed and high speed, respectively, compared to not considering the aircraft wheel constraints. Additionally, with the consideration of constraints at both ends of the aircraft wheels, the vertical acceleration of the nose landing gear's center of mass decreased to 20% and 57% at low speed and high speed, respectively, compared to not considering the aircraft wheel constraints. An analysis of the vertical vibration acceleration of the towing vehicle under different wheel constraint conditions found that the RMS value of the vertical vibration acceleration of the towing vehicle's center of mass was minimized when the clamping angles of the clamping mechanism to the nose landing gear wheels were 63° and 64°, respectively. Under this clamping angle, the influence of the clamping forces at both ends of the clamping mechanism on the vertical vibration acceleration of the towing vehicle was minimal. The research results provide valuable reference for the direct constraints between the clamping mechanism and the nose landing gear wheels in the aircraft towing slip-out system.

Influence of constant feed per tooth via spindle speed adaption on groove quality in micro milling

Adjustments of the feed per tooth in a spindle with an asynchronous motor and mechanical clamping can lead to reduced groove quality, resulting in increased burr formation, inferior surface quality, and radial run-out during changes in spindle speed. In turn, a constant feed per tooth during milling offers advantages for tools and machining processes.This study aims to optimize groove quality during micro milling with a constant feed per tooth, achieving reduced burr formation, improved surface quality, and the elimination of radial run-out. Experiments were conducted on a tool spindle with a synchronous motor, considering both constant and non-constant feed per tooth. The influence of the toolholder type and tool clamping repeatability was considered.Using the synchronous motor and a constant feed per tooth, a length change of the tool spindle was observed during rotational speed variations due to compression/expansion. This change was absent with a non-constant feed per tooth. No adverse effects on groove quality were found with varying feed per tooth.The results demonstrate that a synchronous motor enhances groove quality during micro milling with varying spindle speeds. Employing a constant feed per tooth requires adjustments in cutting depth to compensate for the observed compression/expansion.