Torsion Springs
Torsion springs are a type of helical coil spring designed to resist twisting forces (or torsion) as introduced by angular displacement of the torsion spring legs, which are straight segments of wire that protrude perpendicular to the end of the helical coil spring body. When an applied load displaces these ends by an angular rotation that tries to twist the coils into a tighter wind, the helical coils resist the forces. In this way, a torsion spring will shrink slightly in body diameter and increase in length when subjected to a load. When the rotational force is released, the spring returns to its previously wound position, releasing the stored energy.
Applications
Depending on the application, torsion springs may operate cyclically, storing and releasing this torsional energy during operation, or they may serve as a continuous energy store, retaining objects in a fixed position for extended periods. Notable household examples of such torsion spring mechanisms include wooden clothespins, paper clipboards, and recessed lighting retention fixtures.
In applications, the torsion spring facilitates out-of-plane motion of parts or components. For example, torsion springs in aerospace mechanisms move aerodynamic control surfaces as part of ailerons and wing flap assemblies.
In complex applications, custom torsion springs with specific torque and rotational requirements are integrated into counterbalance systems for use in heavy industrial machinery, such as lifting equipment for hydraulic systems, mechanical presses, and actuator return mechanisms. A simple example of a torsion spring-driven counterbalance system is a residential garage door mechanism.
Key Specifications
Torsion springs are defined by their Inner Diameter, Wire Diameter, Leg Length, Number of Coils, and Angle between Legs (also known as Leg Configuration).
The Spring Rate is defined as the torque required to rotate two legs toward the winding direction and measures the torque at the spring legs needed to rotate the coils by a single degree of angular rotation (denoted as lbf-in per degree)
Additionally, the Wind Direction establishes the direction of the helical coil wind. Torsion springs are either left-hand wind (clockwise) or right-hand wind (counterclockwise). The double torsion spring is a specialized torsion spring consisting of a single wire with one right-hand and one left-hand wind, creating two torsion springs connected in parallel.
Common torsion spring materials include music wire or stainless steel, and various alloys. Additional custom surface finish coatings and treatment options, including passivation and plating, can provide additional fatigue and corrosion resistance as needed.
Benefits
Torsion springs provide precise torque and motion control within a wide range of angular displacement, making them ideally suited for lever or pivot mechanisms, where perpendicular motion or displacements are present within a mechanism. They offer compact, smooth, and reliable performance across a wide range of mechanisms and industries.
Custom torsion springs are available in various leg orientations, along with custom end configurations such as straight, bent, or hooked to integrate seamlessly into almost any design envelope and application.
Torsion Spring Selection Guide & Technical Information
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