What is Torsion spring: Definition and 21 Discussions

Torsion coefficient links here.

A torsion spring is a spring that works by twisting its end along its axis; that is, a flexible elastic object that stores mechanical energy when it is twisted. When it is twisted, it exerts a torque in the opposite direction, proportional to the amount (angle) it is twisted. There are various types:

A torsion bar is a straight bar of metal or rubber that is subjected to twisting (shear stress) about its axis by torque applied at its ends.
A more delicate form used in sensitive instruments, called a torsion fiber consists of a fiber of silk, glass, or quartz under tension, that is twisted about its axis.
A helical torsion spring, is a metal rod or wire in the shape of a helix (coil) that is subjected to twisting about the axis of the coil by sideways forces (bending moments) applied to its ends, twisting the coil tighter.
Clocks use a spiral wound torsion spring (a form of helical torsion spring where the coils are around each other instead of piled up) sometimes called a "clock spring" or colloquially called a mainspring. Those types of torsion springs are also used for attic stairs, clutches, and other devices that need near constant torque for large angles or even multiple revolutions.

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  1. T

    Will this door with torsion spring survive?

    I am trying to design a small box with a hinged door/lid that opens with a torsion spring. When closed, the door will latch onto a mechanism where the open button is, and when the button is pressed this mechanism will slide away, removing the latch out of the way so that the door can fly open...
  2. P

    How fast will this torsion spring open a lid?

    Hi, I'm designing a small container with a spring loaded hollow rectangular lid. I want the lid to open when a button is pressed, so I have a torsion spring at the hinge. I want to know if the spring I selected is able to open the lid and also how long it would take to open 90°. Below is a...
  3. coldadler

    How can I calculate the reaction forces of a torsion spring on a wall?

    Hi guys, I am working on design where I am using a torsion spring. And I need make an analysis and see the deflection of the walls. How can I calculate the forces that applied from Spring's legs to walls. Thank you all in advance.
  4. bpaliwal

    Solving Torsion Spring Problem with 100 lb Force

    I am struggling through a problem in one of my designs and would appreciate some help. Please refer to the image attached. Problem Description: S = Torsion spring F = fixed point T = tire A tire is attached to a torsion spring through an arm as shown in the image. The torsion spring has one...
  5. saaaaam

    Calculate RPM given the force of a torsion spring

    Homework Statement I've got a flywheel of Inertia = 0.0019302kg/m^2 (found via solidworks), when a torsion spring is released, a force of 10N acts on the wheel via astring attached 0.065m above and 0.0325m to the right of the wheel's axis at an angle of 40 degrees. Homework Equations What is...
  6. M

    How Can I Ensure My Torsion Spring Is Strong Enough for the Load?

    Hi guys, I am working on design where I am using a torsion spring to hold a certain load. How can I calculate if the spring I am designing is strong enough to hold the load and prevent it from slipping down? This is music wire 2mm diam spring, 90deg travel, 60mm legs. Please let me know if I...
  7. SilverJW

    I Designing Rehabilitation Equipment for an Upper Limb (arm)

    Before I ask my question, here's a little introduction of myself. I am a college student studying in Bioengineering, so I've been tasked to create an equipment to help rehabilitation for upper limb (any point of the upper limb, doesn't have to be the entire upper limb). So I have this initial...
  8. B

    How a spiral torsion spring works

    How spiral torsion spring (used in mechanical watches to store energy) works? physics behind it ? ... I googled it but haven't got a clue. Where should I look for proper and detailed info.
  9. Buggsy GC

    How do i find the spring constant for a rope torsion spring

    I have built a torsion wheel catapult (Mangonel) for an assignment,and I need to do some theoretical calculations about the displacement, velocity and time of the projectile, the problem is I don't know how to calculate the spring constant without the displacement of the spring (x) and i don't...
  10. H

    Can adjustable torsion springs be used in suspension systems?

    Hi, Is there anything like adjustable torsion spring, even if it is non-helical spring based (such as say hydraulic or pneumatic). As in you can change their stiffness/spring rate? I know that there are so many videos on adjustable springs on garage doors but I think all they do is adjust...
  11. N

    Torsion spring calcualtion for 12 ounces of weight

    I am NOT a physics major and clueless to figure out the strength of a custom spring I need to be made. I was hoping someone could help me, either with figuring it out, or turning me to someone/site that may be able to help. Here's the sitch': The spring is for a center kick-stand on a bicycle...
  12. P

    Force calculation - Gripper (Torsion Spring)

    Hi, Currently I am working on a project to find out the force required to open/close the gripper for holding a circular tube. I have used torsion spring between the two gripper and it will work like a clip. The circular tube is SS316 and the gripper is made out of Aluminium 6061. Stainless...
  13. G

    Torsion spring force required to open a door

    I have a heavy door that I am adding torsion springs too in order to make it easier for a human to open. -The door weighs 460lbs. -It is hinged on one side by two heavy duty hinges and uses a thrust bearing in each hinge with a friction coef. of .008 -the effective radius of the thrust bearing...
  14. A

    Storing energy in a torsion spring

    Hello! This might be a seriously obvious question but... if I were to wind up a torsion spring, such as the type found in a clock movement, and then not release it, how long could that energy stay stored? Presumably it depends on the material used but could it hold it's energy for...
  15. F

    How Do You Calculate Torsion Spring Parameters?

    1. Problem statement. 2. Relative formulas http://en.m.wikipedia.org/wiki/Torsion_spring 3. Attempt. Part a) Since I am given the arc length S and radius, I use the equation s = r(theta) and I solve for theta, with r being the length of the rod and the addition of the radius of the ball...
  16. B

    Maximizing Projectile Distance with Torsion Spring Catapult

    Homework Statement Determine maximum distance an one ounce projectile can be launched with a torsion spring catapult. Homework Equations E = F * d = 1/2 * m * v02Note: Theta is the measurement of how far the lever arm is being pulled back. Am I missing something?
  17. S

    Finding the spring constant of a torsion spring.

    Hi, How would I go about finding the spring constant of a bundle of nylon rope acting as a torsion spring? I know the length. I don't know the width of the bundle. When twisted I wanted roughly 6cm diameter (is that a wrong method)? I ll be twisting it by 1080 degrees. When twisted...
  18. E

    Calculating Torsion Spring Constant | 20 Turns, 6mm Mean Dia, ASTM A228 Material

    Homework Statement I need to calculate the spring constant of a torsion spring. Turns : 20 Mean Diameter : 6mm Wire Diameter : 2mm Material : ASTM A228 Arm Length : will be negligible, as they will be fixed Orientation : Arms inlineHomework Equations k=\frac{Ed^4}{10.8DN} The Attempt at a...
  19. D

    How to Design a Torsion Spring for a Carousel Loading Mechanism?

    Hi there, needing some help with a torsion spring application...I'm looking to use a torsion spring to load a carousel (which is about 400mm diameter, 100mm height and weighs about 2.5-3Kg) so someone will turn this carousel (onto a base) which will load the torsion spring...the spring will be...
  20. Y

    Solving a beam and a torsion spring

    Homework Statement let there be a beam connected to a wall at one end (left). in the other end there is a cylinder attached to the beam with an inertia moment of I0 the cylinder is then connected to a torsion spring which is connected to a right wall the beam (cantilever) has a inertia...
  21. M

    Torsion Spring Catapult Velocity

    I'm trying to design a simple torsion spring catapult to launch a 0.15kg ball at a velocity of 35 m/sec at the moment of separation. The ball will be in direct contact with the unrestrained end of the spring. As a starting point, I'm planning a 0.3m length for that "arm" end of the spring as...