The spiral spring coils by the steel wire, and it has five types. Their pull limit respective is 5N, 3N, 2N, 1N, 0.5N. The surface nickel-plates. The spring consists of two parts that are up and down ends. The upper end is circle ring. The down end consists of triangular film, bar with hook and needle.

Function

It applies for the experiment in physics in secondary school.

1. When spiral spring produces deformation under getting the external force, the external force will produce elastic deformation in the elastic limit. In addition, when remove the external force, the spring will become original state and deformation disappear. (When external excess the elastic limit, it will happen Fan sexual deformation. However, when remove the external force, the deformation will not disappear).
2. In the elastic limit, the stretch-out length of spring varies with the external force. (Validate by the Hooke’s law)
3. The calibration principle of spring ergometer.

Structure

The spiral spring coils by the steel wire, and it has five types. Their pull limit respective is 5N, 3N, 2N, 1N, 0.5N. The surface nickel-plates. The spring consists of two parts that are up and down ends. The upper end is circle ring. The down end consists of triangular film, bar with hook and needle.

Technological Index

1. A place that has red lacquer on the triangular film is effective work turns.
2. In the work limit charge, the non-linear tolerance of relative stiffness is not more than 5% that is spring stiffness of each part.
3. Five types of spring have different stiffness: 5N is 0.025N/mm, 3N is 0.015N/mm, 2N is 0.01N/mm, 1N is 0.005N/mm, and 0.5N is 0.0025N/mm.

Use

Prepare the physical bracket for oneself (base, buckling, bar and fixed clip) and homemade scale plate (makes by cardboard). Or do the experiment according to the showing of teaching material. During the experiment, hang the spring at the suitable height of bracket, and nip ruler vertically at the buckling that approaches the spring. Make the needle get close to the cardboard. Mark the origin. After hang the poise in the hook, and the weight of poise is marked pull of spring 1/5, 2/5, 3/5, 4/5, 5/5. Then measure the different stretched value of spring, and make the value mark the dividing line on the white cardboard. Therefore, it not only can validate with scale that the external force varies with the stretched length of spring, but also can understand the calibration principle of ergometer. If spin the triangle film, increase and reduce the turns of spring, the stretched value will increase with the spring turns. On contrary, it will shorten. However, the external force still varies with the stretched length.

Notice

1. When measure, the needle should be vertical correction with hook bar to reduce parallax.
2. When pull the spring, should use the pull carefully. If the pull excesses the elastic limit, the spring will not recover.
3. After using, put it in the box. Avoid pressing and heating spring.