Torsion spring

About: Torsion spring is a research topic. Over the lifetime, 9342 publications have been published within this topic receiving 50926 citations. The topic is also known as: Torsion bar.

Peterson's Stress Concentration Factors

Abstract: Index to the Stress Concentration Factors. Preface for the Third Edition. Preface for the Second Edition. 1. Definitions and Design Relations. 1.1 Notation. 1.2 Stress Concentration. 1.3 Stress Concentration as a Two-Dimensional Problem. 1.4 Stress Concentration as a Three-Dimensional Problem. 1.5 Plane and Axisymmetric Problems. 1.6 Local and Nonlocal Stress Concentration. 1.7 Multiple Stress Concentration. 1.8 Theories of Strength and Failure. 1.9 Notch Sensitivity. 1.10 Design Relations For Static Stress. 1.11 Design Relations for Alternating Stress. 1.12 Design Relations for Combined Alternating and Static Stresses. 1.13 Limited Number of Cycles of Alternating Stress. 1.14 Stress Concentration Factors and Stress Intensity Factors. References 2. Notches and Grooves. 2.1 Notation. 2.2 Stress Concentration Factors. 2.3 Notches in Tension. 2.4 Depressions in Tension. 2.5 Grooves in Tension. 2.6 Bending of Thin Beams with Notches. 2.7 Bending of Plates with Notches. 2.8 Bending of Solids with Grooves. 2.9 Direct Shear and Torsion. 2.10 Test Specimen Design for Maximum Kt for a Given r D or r H 76. References. Charts. 3. Shoulder Fillets. 3.1 Notation. 3.2 Stress Concentration Factors. 3.3 Tension (Axial Loading). 3.4 Bending. 3.5 Torsion. 3.6 Methods of Reducing Stress Concentration at a Shoulder. References. Charts. 4. Holes. 4.1 Notation. 4.2 Stress Concentration Factors. 4.3 Circular Holes with In-Plane Stresses. 4.4 Elliptical Holes in Tension. 4.5 Various Configurations with In-Plane Stresses. 4.6 Holes in Thick Elements. 4.7 Orthotropic Thin Members. 4.8 Bending. 4.9 Shear and Torsion. 5. Miscellaneous Design Elements. 5.1 Notation. 5.2 Shaft with Keyseat. 5.3 Splined Shaft in Torsion. 5.4 Gear Teeth. 5.5 Press- or Shrink-Fitted Members. 5.6 Bolt and Nut. 5.7 Bolt Head,Turbine-Blade, orCompressor-Blade Fastening (T-Head). 5.8 Lug Joint. 5.8.1 Lugs with h d 0 . 5. 5.8.2 Lugs with h d 0 . 5. 5.9 Curved Bar. 5.10 Helical Spring. 5.10.1 Round or Square Wire Compression or Tension Spring. 5.10.2 Rectangular Wire Compression or Tension Spring. 5.10.3 Helical Torsion Spring. 5.11 Crankshaft. 5.12 Crane Hook. 5.13 U-Shaped Member. 5.14 Angle and Box Sections. 5.15 Cylindrical Pressure Vessel with Torispherical Ends. 5.16 Tubular Joints. References. Charts. 6. Stress Concentration Analysis and Design. 6.1 Computational Methods. 6.2 Finite Element Analysis. 6.3 Design Sensitivity Analysis. 6.4 Design Modification. Index.

Normal and torsional spring constants of atomic force microscope cantilevers

Abstract: Two methods commonly used to measure the normal spring constants of atomic force microscope cantilevers are the added mass method of Cleveland et al. [J. P. Cleveland et al., Rev. Sci. Instrum. 64, 403 (1993)], and the unloaded resonance technique of Sader et al. [J. E. Sader, J. W. M. Chon, and P. Mulvaney, Rev. Sci. Instrum. 70, 3967 (1999)]. The added mass method involves measuring the change in resonant frequency of the fundamental mode of vibration upon the addition of known masses to the free end of the cantilever. In contrast, the unloaded resonance technique requires measurement of the unloaded resonant frequency and quality factor of the fundamental mode of vibration, as well as knowledge of the plan view dimensions of the cantilever and properties of the fluid. In many applications, such as frictional force microscopy, the torsional spring constant is often required. Consequently, in this article, we extend both of these techniques to allow simultaneous calibration of both the normal and torsional spring constants. We also investigate the validity and applicability of the unloaded resonance method when a mass is attached to the free end of the cantilever due to its importance in practice.

Rocker switch with centering torsion spring

Abstract: A rocker switch with a shaft (30) that can be pivoted clockwise or counterclockwise from a neutral position, which reliably returns to the same neutral position without “play”, and which is of simple design. A coil spring (25) which extends around the shaft, has front and rear opposite coil end portions (24, 26) with corresponding spring ends (27, 29), and which has a spring middle (28). Arms mounted on the shaft include a first arm (39′) engaged with the front spring end and a second arm (39) positioned to engage the spring middle. When the shaft is turned clockwise from the neutral position, the arms turn the first spring end (27) and spring middle (28) clockwise while loading only the rear coil end portion (26). When the shaft turns counterclockwise, the spring middle (28) is prevented from turning by a spring center support (43), so only the front coil portion (24) is loaded.

Control of Rotary Series Elastic Actuator for Ideal Force-Mode Actuation in Human–Robot Interaction Applications

Abstract: To realize ideal force control of robots that interact with a human, a very precise actuating system with zero impedance is desired. For such applications, a rotary series elastic actuator (RSEA) has been introduced recently. This paper presents the design of RSEA and the associated control algorithms. To generate joint torque as desired, a torsional spring is installed between a motor and a human joint, and the motor is controlled to produce a proper spring deflection for torque generation. When the desired torque is zero, the motor must follow the human joint motion, which requires that the friction and the inertia of the motor be compensated. The human joint and the body part impose the load on the RSEA. They interact with uncertain environments and their physical properties vary with time. In this paper, the disturbance observer (DOB) method is applied to make the RSEA precisely generate the desired torque under such time-varying conditions. Based on the nominal model preserved by the DOB, feedback and feedforward controllers are optimally designed for the desired performance, i.e., the RSEA: (1) exhibits very low impedance and (2) generates the desired torque precisely while interacting with a human. The effectiveness of the proposed design is verified by experiments.