Spiral Spring Research Articles

Design of Integrated Dual Spiral Spring and Rotary Hydraulic Damper System for Torsional Vibration Damping in Pesticide Sprayer Gearbox

Design of Integrated Dual Spiral Spring and Rotary Hydraulic Damper System for Torsional Vibration Damping in Pesticide Sprayer Gearbox

Prediction of quasi-static mechanical properties of flexible porous metal rubber structures in ultra-wide temperature range

Metal rubber, which has the advantages of low density, strong environmental adaptability, and excellent design flexibility, is widely applied in manufacturing industries such as the aerospace, shipping, and automotive industries. Based on the research object of flexible porous metal rubber (FPMR) structures made of high-temperature elastic alloys, this study established a constitutive model for the quasi-static mechanical properties of FPMR structure under ultra-wide temperature range conditions. Firstly, the forming mechanism and the influencing factors of the static stiffness properties of the FPMR micro-structure were analyzed. Then, the theoretical model of the FPMR micro-element spring was established by applying the cylindrical spiral compression spring stiffness theory, and the theoretical model was corrected based on the large deformation theory and numerical analysis methods. A comparative analysis was carried out through the corrected theoretical model and the test results of different test samples. And the results show that the corrected theoretical model can comprehensively reflect the nonlinear quasi-static stiffness characteristics of the FPMR structure in an ultra-wide temperature range. More importantly, by comparison with the prediction models proposed by other scholars, it is proved that the model proposed in this paper has higher prediction accuracy and the goodness of fit R2 is closer to 1, which provides a theoretical basis for the application of metal rubber in flexible support structures under ultra-high temperature environments.

Open-source spring-driven syringe pump with 3D-printed components for microfluidic applications

The operation of microfluidic devices requires precise and constant fluid flow. Microfluidic systems in low-resource settings require a portable, inexpensive, and electricity-free pumping approach due to the rising demand for microfluidics in point-of-care testing (POCT). Open-source alternatives, employing 3D printing and motors, offer affordability. However, using motors require electrical power, which often relies on external sources, hindering the on-site use of open-source pumps. This study introduces a spring-driven, 3D-printed syringe pump, eliminating the need for an external power source. The syringe pump is operated by the flat spiral spring’s torque. By manually winding up the mainspring, the syringe pump can be operated without electricity. Various flow rates can be achieved by utilizing different syringe sizes and choosing the right gear combinations. All the parts of the syringe pump can be fabricated by 3D printing, requiring no additional components that require electricity. It operates by winding a mainspring and is user-friendly, allowing flow rate adjustments by assembling gears that modulate syringe plunger pushing velocity. The fabrication cost is $25–30 and can be assembled easily by following the instructions. We expect that the proposed syringe pump will enable the utilization of microfluidic technologies in resource-limited settings, promoting the adoption of microfluidics. Detailed information and results are available in the original research paper (https://doi.org/10.1016/j.snb.2024.135289).

Failure of an electric rocking device to improve neonatal sleep.

We wanted to investigate whether an electric rocking device (Swing2Sleep, Neumünster, Germany), sold with the claim to promote infant sleep, would increase total sleep time or reduce sleep latency once infants are put therein. In a randomised crossover design, 20 infants (median gestational age at birth 31.7 weeks, range 25-39) were placed to sleep either first with the device rocking, then not rocking (or vice versa) for 5-7 h each. The device consisted of a hammock with three spiral springs that performed vertical swings at a rate of 100/min and an amplitude of 2.5 cm. There was no significant difference in %time spent asleep (83 (22-97) vs. 85% (49-96)), sleep latency (7.7 (2-45) vs. 12.3 (4-42) min), sleep fragmentation (1.3 (0.5-2.3) vs. 1.1 (0.2-5.5)) or efficiency (0.8 (0.2-1.0) vs. 0.9 (0.5-1.0)) between both conditions. At its recommended settings, the device did not achieve its intended effect in these infants.

Integrated Simulation Research of Multi-natural Energy-driven Unmanned Surface Vehicle

In response to the limitations of existing unmanned surface vehicles in complex marine environments, where they often fail to meet the requirements for extended endurance, broad operational range, offshore missions, and prolonged operational durations, an autonomous Unmanned Surface Vehicle (NUSV) has been designed and developed. The NUSV is propelled by wind, solar, and wave energy sources. Concerning wind energy, a micro wind energy storage mechanism based on a spiral spring has been designed to enable power generation in low-wind conditions. A wave energy transmission device, complete with a dynamic model, has been devised for wave energy. This device converts torque generated from wave action in different directions into a unified torque, providing continuous power to drive the generator. Solar energy is harnessed using Maximum Power Point Tracking (MPPT) algorithms to ensure optimal operation of the solar panels. The electrical energy generated from these three natural sources is stored using Pulse Width Modulation (PWM) and DC-DC Boost converters. A programmable logic controller manages and allocates this stored electrical energy for the NUSV’s equipment, including underwater propulsion systems, surface cameras, laser radar, GPS, and other electronic devices. This integration of wind, solar, and wave energy sources enables the NUSV to meet power demands, allowing for long-duration operations at sea, extended offshore missions, wide operational ranges, and prolonged mission durations.

The Numerical Analysis considering contact between the plate of the non-contact type Spiral Springs

The Numerical Analysis considering contact between the plate of the non-contact type Spiral Springs

Automated resolution of the spiral torsion spring inverse design problem

Many mechanical applications take advantage of spiral torsion springs due to their robustness, compactness, and simplicity. Brand-new manufacturing methods allow to create spiral springs with unconventional geometries and materials that suit a wider range of uses demanding either linearity or nonlinearity. Designing a spiral torsion spring with a nonlinear desired torque curve may be a great challenge, due to their many degrees-of-freedom (length, width, thickness, arbor, and barrel diameters, etc.) and the complexity of the geometrical and mechanical requirements to ensure their manufacturability, system compatibility, operation safety and reliability; and the solution is never unique. This manuscript proposes and validates an innovative methodology for the resolution of this inverse design problem based on the application of a nonlinear restrained global optimization algorithm. This algorithm is adjusted to converge, out of the infinity of designs that match the desired torque curve and hold all the functional and manufacturing constraints, to a design solution that minimizes strip mass. The methodology is built on a formulation for the calculation of the torque curve of a generalized spiral spring, with or without coiling and with any along-the-length cross-section, already published by the authors.

Investigation on the free vibration characteristics of vertical quasi-zero stiffness isolation system considering the disc spring's loading position

This study investigates a quasi-zero stiffness (QZS) isolation system designed for vertical vibration control in isolation structures. The QZS characteristics are achieved by connecting a negative stiffness disc spring in parallel with the linear positive stiffness spiral spring. Initially, the force-displacement relationship of the disc spring is established, taking into account the loading position, and validated through static experiments. Subsequently, the free vibration equations of the QZS system are derived. The Jacobi elliptic functions and the Newton-harmonic balance (NHB) method are then employed to study its free vibration characteristics without considering damping. The results demonstrate that the natural vibration period of the QZS system is related to the nondimensional amplitude and the height of the loaded inner cone. Furthermore, the second-order analytical approximate solution obtained via the NHB method exhibits remarkable accuracy. Finally, the critical damping ratio of the damped QZS isolation system is investigated using a numerical approach. The findings indicate that the critical damping ratio is only correlated with the nondimensional amplitude. This study addresses the gaps in existing research and provide recommendations for the parametric design of vertical QZS isolation system.

A novel permanent magnet vibration isolator with wide stiffness range and high bearing capacity

Quasi-zero stiffness (QZS) vibration isolators have attracted extensive attention because of their excellent performance in low-frequency vibration isolation and high bearing capacity. However, its practical engineering application remains challenges due to the magnitude and adaptability of the negative stiffness. This paper proposes a permanent magnet type variable stiffness (PMVS) mechanism with a wide stiffness range from negative to positive. Based on the semi-analytical model of magnetic force, the QZS isolator composed of the spiral spring in parallel with the PMVS mechanism is developed, which has both stiffness adjustment and load adaptability. The nonlinear dynamic equation with 5th polynomial restoring force is established then solved by the harmonic balance method (HBM). The dynamic behaviours is investigated and validated through the experimental prototype and good isolation performance is observed. Building upon the wide stiffness adjustment and large magnitude of the PMVS mechanism. the proposed isolator achieves a stiffness range of 4.15–153.45 N/mm under a safe load up to 120 kg, which implies that the natural frequency of the isolator can reach an ultralow value of 0.93 Hz within the safe load (120 kg).

Fully 3D-printed, nonelectric, spring-powered syringe pump for operating microfluidic devices

Microfluidic devices require a precise and steady flow for fluid control. The high demand for microfluidics in point-of-care testing (POCT) necessitates a portable, low-cost, and electricity-free pumping method for operating microfluidic platforms in low-resource settings. This study presents a fully 3D-printed and portable syringe pump operated by torque from a flat spiral spring. The syringe pump can be operated by manually winding up the spring, and various flow rates can be obtained using different syringe sizes and selecting appropriate gear combinations. It generated a steady flow rate ranging from 1.4 µL/min to 12.0 µL/min with high repeatability. The pump is suitable for the on-site use of microfluidic platforms because it does not require electricity and does not occupy a large space. The 3D printed pump proposed in this study is named precise, rapid-prototyped, nonelectric, torque-driven (PRNTD) pump. The versatility and utility of the pump are demonstrated by generating a linear concentration gradient using a microfluidic gradient generator and microdroplets using a T-channel microfluidic chip. The PRNTD pump can facilitate the on-site application of microfluidic platforms in resource-limited settings and contribute to the widespread use of microfluidic technologies.

A dual-kinetic energy harvester operating on the track and wheel of rail deceleration system for self-powered sensors

Alternative energy sources play a crucial role in Outback rail systems, where electrical infrastructure is unavailable for automated power devices used for traffic lights, surveillance cameras, sensors, and other safety equipment at railway stations and intersections. The current study proposes an innovative dual-kinetic energy harvester design to reduce train speed at intersections and before it comes to a halt at the station. Additionally, it harvests energy from both the train track and wheel simultaneously. The proposed device consists of three main units. The first unit utilizes vibrational movement based on a rack pinion. An efficient dual-kinetic energy harvesting system has been developed, utilizing a novel concept that captures the vibration energy generated by the movement of the rail under the influence of the train’s weight. Additionally, as the train passes at high speed, the train wheel’s energy will be transmitted to the top of the device, moving the rack to a depth of 30 mm. A spiral spring is employed to restore the rack to its initial position after the wheel has passed. The tension force of the spring causes the rack to adhere to the track, enabling the transmission of vibrations generated by the track’s movement and releasing energy, causing the motion to be induced during the return stroke. The second component is the transmission unit. The bidirectional rotational motion from the rack pinion is converted into unidirectional rotational motion using three bevel gears, two roller clutches, and a planetary gearbox to enhance the rotations of the generator shaft. The third component is a 1500 W/180 V DC motor for electricity generation. Lastly, the charging circuit was developed to recharge supercharged capacitors. The proposed system was installed before the railway station, and practical tests were conducted, which showed an efficiency of up to 55%.

Accelerated degradation data analysis based on inverse Gaussian process with unit heterogeneity

The unit heterogeneity of products and the nonlinear parameter-stress relationship often exist in practice. Therefore, considering the unit heterogeneity, the nonlinear accelerated model and inverse Gaussian process are developed to depict the accelerated degradation data. On the other hand, this more realistic model leads a challenge to derive the model parameter interval estimation. Thereby, a novel two-step interval estimation method is proposed for the proposed accelerated degradation model. First, generalized confidence intervals of the parameters characterizing random effect are derived from the Cornish–Fisher expansion, and their cumulative distribution functions are obtained. Then, using the generalized pivotal quantity procedure, generalized confidence intervals of the accelerated model parameters are derived. In addition, generalized confidence intervals of predictive reliability indexes are derived to guide the practical application. Finally, simulation studies and two real examples on Spiral springs and integrated circuit devices are presented to demonstrate the implementation of the proposed method.

Method and finite element verification of indentation calculation for a novel air-spring mattress: for estimating spinal alignment in sleep postures

PurposeThis study aimed to develop a method to calculate the mattress indentation for further estimating spinal alignment.Design/methodology/approachA universal indentation calculation model is derived based on the system theory, and the deformation characteristics of each component are analyzed by the finite element (FE) model of a partial air-spring mattress under the initial air pressure of 0.01–0.025 MPa. Finally, the calculation error of the model is verified.FindingsThe results indicate that the indentation calculation model could describe the stain of a mattress given the load and the constitutive model of each element. In addition, the FE model of a partial air-spring mattress can be used for further simulation analysis with an error of 1.47–3.42 mm. Furthermore, the deformation of the series system is mainly contributed by the air spring and the components directly in contact with it, while the top component is mainly deflection deformation. In addition, the error of the calculation model is 2.17–5.59 mm on the condition of 0.01–0.025 MPa, satisfying the engineering application. Finally, the supine spinal alignment is successfully extracted from the mattress indentation.Research limitations/implicationsThe limitation of this study is that it needs to verify the practicality of the indentation calculation model for the Bonnier spiral spring mattress. The main feature of the Bonnier spring mattress is that all springs are connected, so the mattress deflection and neighborhood effect are more significant than those of the air-spring mattress. Therefore, the applicability of the model needs to be tested. Moreover, it is worth further research to reduce the deformation error of each component.Practical implicationsAs part of the series of studies on the intelligent air-spring mattress, the indentation-based evaluation method of spinal alignment in sleep postures will be studied for hardness and intelligent regulation based on this study.Social implicationsThe results of this research are ultimately used for the intelligent adjustment of air-spring mattresses, which automatically adjusts the hardness according to the user's sleep postures and spinal alignment, thus maintaining optimal spinal biomechanics. The successful application of this result could improve the sleep health of the general public.Originality/valueBased on the series system theory, an indentation calculation model for mattresses with arbitrary structure is proposed, overcoming the dependence of parameters on materials and their combinations when fitting the Burgers model. Further, the spinal alignment in supine posture is extracted from the indentation, laying a theoretical foundation for further recognition and adjustment of the spinal alignment of the intelligent mattress.

Determination of the form of a spiral spring in a free state

The object of research. This article deals with a spiral spring made of tape material with a rectilinear cross-section.
 Investigated problem. If one end of a metal ruler is pinched, and a certain force is applied to the other end, it will bend under the action of the generated moment. The magnitude of the moment depends on the applied force and the length of the ruler. Therefore, the amount of deflection will increase with the increase of these parameters, and the shape of the ruler may take the spiral form. After the termination of the external load, the ruler will regain its original shape, that is, it will become straight. However, such spiral springs do not exist in practice. For compact sizes, the spring in its free state also has a spiral shape. In this regard, the purpose of the study is to find the elastic axis of a tape spiral spring in a free state, which under the action of a concentrated force takes a given shape.
 The main scientific results. The shape of the spiral spring in the free state is determined, which under the action of the applied force acquires the desired shape, which does not lead to the occurrence of frictional forces between adjacent coils.
 The area of practical use of research results. Spiral springs are widely used. One example is mechanical clock movements and measuring devices, in which the determination of indicators depends on the applied force that "unwinds" or "twists" the spring.
 Innovative technological product. The paper calculates the elastic axis of a spiral spring in a free state according to its given final shape, taking into account the moment that arises as a result of the applied force at the end of the spring. For this, the nonlinear theory of absolutely elastic bending using the methods of differential geometry of curved lines as a function of the own length of the arc of the spring axis is applied.
 The scope of application of the innovative technological product. The results obtained in the study can be used in the manufacture of spiral springs for various purposes, as well as for the accumulation of potential energy in the absence of other sources

Suspended-Load Backpacks to Reduce the Cost of Carrying Loads with Energy Scavenging Potential—Part 2: Bio-Inspired Pre-Rotation Design

Backpack transportation is everywhere in daily life. Suspended-load backpacks (SUSBs) based on forced vibration have attracted lots of attention because of their ability to effectively reduce the cost on the body during motion. The smaller the natural frequency of SUSBs, the better the cost reduction. The natural frequency is determined by the elastic components of SUSBs. It is currently common to use rubber ropes and pulleys as elastic components. In the first part of this paper, we propose a pre-compression design for SUSBs, which has a simple structure and breaks through the limitation of rubber material. To make the natural frequency small enough, rubber ropes and compression springs require sufficient space. This leads to the current SUSBs being large and, therefore, not suitable for children to carry. Inspired by biology, here we propose a new design strategy of pre-rotation with pre-rotation spiral springs as elastic components. The pre-rotation design not only has the advantages of avoiding the inconvenience of material aging and the ability to adjust the downward sliding distance of the backpack but also greatly saves the space occupied by the elastic components, which can be adopted by small SUSBs. We have developed a theoretical model of the pre-rotation SUSBs and experimentally confirmed the performance of the pre-rotation SUSBs. This work provides a unique design approach for small SUSBs and small suspended-load devices. And the relative motion between the components inside the SUSB has a huge potential to be used by triboelectric nanogenerators for energy scavenging.

Design and analysis of a passive exoskeleton with its hip joint energy-storage.

A novel passive hip exoskeleton has been designed and built with the aim of reducing metabolic consumption during walking by a passive way of storing the negative mechanical energy in the deceleration phase and releasing it in the acceleration phase. A ratchet spiral spring mechanism with a set of double stable switches is designed inside the exoskeleton for the above purpose. An analysis is conducted on the mechanism and the switching timing for the energy management to automatically store or release the energy according to the biomechanics of walking. In addition, a gravity-balance mechanism embedded inside the exoskeleton is designed as well to minimize the influence of the lower limb weight on muscle work. Human-exoskeleton interaction has been studied using the Opensim software, and simulation results demonstrated the effectiveness of the exoskeleton in reducing metabolic consumption during walking. An exoskeleton prototype has been built and tested with experiments measuring assistive torque and surface electromyography signal, confirming the effectiveness of the gravity-balance mechanism and energy-storage method, as well as the exoskeleton's actual assistive effect.

Mechanical behavior and improved model of multi-strand entangled metallic wire material

This work presents the experimental characterization and improved model of multi-strand entangled metallic wire materials (MS-EMWMs). MS-EMWM is a novel damping material made of several strands of entangled wires using a modified manufacturing process. Six batches of specimens were fabricated and tested under quasi-static loading. Secant stiffness and loss factor were calculated to indicate the mechanical properties. The results showed that MS-EMWM has the characteristics of high damping energy dissipation compared to EMWM. A micro-multi-strand spiral spring model was proposed to predict the mechanical properties of MS-EMWM. The probability distribution of micro-spring pairs between wires was used to characterize the random combination of materials. According to the results, the improved model can effectively reflect the mechanical behavior of MS-EMWM. The mechanical properties of MS-EMWM were predicted by the coefficient matrix obtained by particle swarm optimization. Through the prediction and test results, the predicted results are acceptable.

Improving the oscillating wind turbine model

Disadvantages in the structure of the most common rotary wind generators limit their use. This motivates the development of alternative types of wind turbines, the most promising of which are oscillating wind generators. The object of the study is the structure of an oscillating type wind generator, which provides self-oscillating movement of the blade-wing. The design of the wind generator uses a modified wing shape to provide maximum lift. For this purpose, added elements are the tip and flap, which affect the shape of the wing, its angle of attack, and regulate the direction of the lifting force. The principle of attaching the tip and flap to the wing using spiral springs has been developed. The structure also includes locking magnets that affect the movement of the wing during a turn. The mechanism that drives the self-oscillating mode of operation of the wind turbine was described. This mode occurs under the action of the inertial force of the movement of the wing, the force of elasticity, the repulsive force of the magnets, and the pressure force of the air flow. A computer simulation of the wind generator was carried out using the Ansys CFX software package. The model of the flow around an absolutely rigid body at small values of the Reynolds number was applied. The resulting dynamics of the horizontal movement of the wing of the wind turbine make it possible to use it for energy generation already at a wind speed of 2 m/s. The low cost of the wing and the automatic regulation of its movement make it possible to install many wings to increase the power of the wind generator. Thus, the improved wind turbine is low-cost, harmless to birds, has self-regulation of wing movement and can use the low-speed component of the wind, which significantly expands the geography of its operation. It is possible to transfer the proposed technological solutions for the construction of hydroelectric generators

Design and Verification of a Novel Energy Harvester for Tire Pressure Monitoring Systems

With the development of intelligent tires, the tire pressure monitoring system (TPMS) has become a standard safety feature in cars. However, the existing TPMS has limited ability to monitor tire pressure in real time due to the passive power supply device’s low power output. This work presents a conceptual design for a novel energy harvester for TPMS (NEH-TPMS) based on a mechanical structure to recover energy. The motion of the mechanical structure is driven by the deformation of the tire in contact with the ground. The energy is recovered and released by a spiral spring to accomplish the functions of power generation and charging. Mathematical models are created based on the NEH-TPMS’s movements. The simulation results indicate that the NEH-TPMS’s power generation capacity is greater than that of existing energy harvesters and can satisfy the TPMS’s power supply requirements. This work uses finite element analysis and hierarchical analysis to optimize the shape of the NEH-TPMS. The parameters of the spiral spring are optimized using simulated annealing and genetic algorithms. NEH-TPMS has been enhanced to provide greater energy storage capacity. Finally, a prototype was built to verify the structure’s feasibility. The experimental results are consistent with the simulated results. This NEH-TPMS offers an efficient means of enhancing the power generation efficiency of the passive power supply device for TPMS.

Thin Glass Micro Force Plate Supported by Planar Spiral Springs for Measuring Minute Forces.

Microforce plates are indispensable tools for quantitatively evaluating the behavior of small objects such as tiny insects or microdroplets. The two main measurement principles for microforce plates are: the formation of strain gauges on the beam that supports the plate and the measurement of the deformation of the plate using an external displacement meter. The latter method is characterized by its ease of fabrication and durability as strain concentration is not required. To enhance the sensitivity of the latter type of force plates with a planar structure, thinner plates are generally desired. However, brittle material force plates that are both thin and large and can be fabricated easily have not yet been developed. In this study, a force plate consisting of a thin glass plate with a planar spiral spring structure and a laser displacement meter placed under the plate center is proposed. The plate deforms downward when a force is exerted vertically on its surface, resulting in the determination of the applied force using Hooke's law. The force plate structure is easily fabricated by laser processing combined with the microelectromechanical system (MEMS) process. The fabricated force plate has a radius and thickness of 10 mm and 25 µm, respectively, with four supporting spiral beams of sub-millimeter width. A fabricated force plate featuring a sub-N/m spring constant achieves a resolution of approximately 0.01 µN.