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"Levers."
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Levers in action
Introduces levers, explains how these simple machines work, and describes some common examples.
Book
Development of a Lever-type Calibration Device
This paper mainly introduces a lever-type calibration device to solve the measurement problem of body scale. The design method and design scheme are introduced to verify the feasibility of the device and realize the automatic calibration of the body scale.
Journal Article
Pressing down : the lever
\"Pressing Down explores the benefits and uses of the lever. RobbO and RobbEE learn how a lever can be formed in three different ways to do different kinds of work--lift and lower, separate, and open.\"-- Provided by publisher.
Book
Emerging Technologies in Displacement Amplification of Lever and Bridge-Type Compliant Mechanism: A Review Article
This review article provides a survey of emerging technologies in displacement amplification of lever-type and bridge-type compliant mechanisms. The displacement amplification is possible with a compliant mechanism. The compliant mechanism is beneficial and efficient because of simplicity in the design and where there is accuracy, compactness, and precision is needed. We can use various categories of displacement amplification of the compliant mechanism depending upon the application. In recent years, displacement amplification of compliant mechanisms gain more attention to the researchers due to the superiority of the mechanical compliant mechanism is compared with a rigid-body mechanism. Displacement amplification compliant mechanism such as bridge types, lever type, a micro-Leverage Mechanism has briefly discussed. The performance parameters such as the principle of working, types of displacement compliant mechanism, fabrication process, operating frequency and displacement amplification ratio are found out
Journal Article
Working with levers
\"We can find levers all around us. Baseball bats, crowbars, seesaws, and wheelbarrows are all examples of levers. The three classes of levers make hard lifting jobs easier with the help of leverage. Each class of lever is set up differently, but has all the same parts. Levers are made up of a plank that pivots at a fulcrum. In this book, readers will learn about the difference between each class of lever, where levers can be found, and how levers make many jobs we do much easier\"-- Provided by publisher.
Book
Design of a symmetrical piezoelectric microgripper based on parallel Scott-Russell and differential lever amplification mechanisms
To address the issue of insufficient gripping stroke of piezoelectric microgrippers, a horizontally symmetric microgripper with differential lever amplification mechanisms was proposed. This structure adopts 2 pairs of Scott-Russell (S-R) mechanisms and reversed S-R mechanisms to construct a parallel amplification mechanism. Then, the output displacements of the S-R and reversed S-R mechanisms are linked to a lever mechanism to create a differential mechanism, which can further improve the output displacement. The kinematic and stiffness models of the microgripper were established by the pseudo-rigid-body model, and the amplification ratio and input stiffness of the microgripper were obtained. Finally, the accuracy of the kinematic and stiffness models was verified by finite element simulation. The simulation results show a total amplification ratio of 65.46, a gripping stroke of 1.3 mm, an input stiffness of 25.87 N/μm, a stroke-to-area ratio of 443, and a first-order natural frequency of 431.4 Hz. The designed microgripper demonstrates cross-scale gripping capability and rapid dynamic response.
Journal Article
Making machines with levers
A clear and straightforward introduction to the science and technology of machines, showcasing the parts of each machine, how each machine works and how they are used in the world around us.
Book
Quality improvement of the primary cable of the handbrake lever: a QFD approach
Quality function deployment is one of the most used tools for the quality improvement of products or services. According to the literature, manufacturing is one of the industries that has benefited most from its employment. Therefore, the purpose of this paper is to illustrate the usability of the quality function deployment in improving the quality of the primary cable of the handbrake lever. In this way, the technical priorities of this product were established by comparison with those of the main competitors in the market and the target values of each technical characteristic of the product were determined. In addition, the attention of the manufacturer of the primary cable of the handbrake lever can be also focused on the fulfillment of the customer expectations.
Journal Article
The diagnostic accuracy of clinical tests for anterior cruciate ligament tears are comparable but the Lachman test has been previously overestimated: a systematic review and meta-analysis
Purpose
The diagnostic accuracy of clinical tests for anterior cruciate ligament injury has been reported in previous systematic reviews. Numerous studies in these reviews include subjects with additional knee ligament injury, which could affect the sensitivity of the tests. Meta-analyses have also been performed using methods that do not account for the non-independence of sensitivity and specificity, potentially overestimating diagnostic accuracy. The aim of this study was to report the diagnostic accuracy of clinical tests for anterior cruciate ligament tears (partial and complete) without concomitant knee ligament injury.
Methods
A systematic review with meta-analysis was performed according to the PRISMA guidelines. Meta-analyses included studies reporting the specificity and/or sensitivity of tests with or without concomitant meniscal injury. Where possible, pooled diagnostic estimates were calculated with bivariate random-effects modelling to determine the most accurate effect sizes. Diagnostic accuracy values are presented for the anterior drawer, Lachman, Lever sign and pivot shift tests overall and in acute or post-acute presentations.
Results
Pooled estimates using a bivariate model for overall sensitivity and specificity respectively were as follows: anterior drawer test 83% [95% CI, 77–88] and 85% [95% CI, 64–95]; Lachman test 81% [95% CI, 73–87] and 85% [95% CI, 73–92]; pivot shift test 55% [95% CI, 47–62] and 94% [95% CI, 88–97]; Lever sign test 83% [95% CI, 68–92] and 91% [95% CI, 83–95]. For specific presentations, the sensitivity and specificity of the Lachman test, respectively, were: complete tears 68% [95% CI, 54–79] and 79% [95% CI, 51–93]; post-acute injuries 70% [95% CI, 57–80] and 77% [95% CI, 53–91].
Conclusions
The pivot shift and Lever sign were the best tests overall for ruling in or ruling out an anterior cruciate ligament tear, respectively. The diagnostic accuracy of the Lachman test, particularly in post-acute presentations and for complete tears, is lower than previously reported. Further research is required to establish more accurate estimates for the Lachman test in acute presentations and partial ligament tears using bivariate analysis.
Level of evidence
III.
Journal Article
Modeling and analysis of bridge lever mechanism based on piezoelectric drive
To enhance the amplification ratio of a single bridge amplification mechanism, a novel bridge-lever amplification mechanism based on hybrid hinges is proposed. This new design combines the symmetry and compactness of traditional bridge mechanisms with the structural flexibility and environmental adaptability of lever mechanisms, achieving a higher amplification ratio. A static model is established by using the compliance matrix method to analyze relative amplification ratios under different hinge configurations. Simulations show optimal performance when the first stage uses V-shaped hinges and the second stage uses blade-shaped hinges. The fabricated mechanism achieves an amplification ratio of 40 and a relative amplification ratio exceeding 0.9, validating the analysis.
Journal Article