Internal structure of tape measure
It's a simple structure, the intermediate shaft is fixed with a scroll spring inner end of the spiral spring is fixed on the outer end of the measuring tape, the shaft is fixed, pull out the feet when the scroll spring is pulled and tightened, loosen the tape can be recovered in elastic effect.
The internal structure of the tape is not too complicated, the middle of a shaft, the shaft is not the shaft has an opening at one end of the disc spring heart inserted in the shaft opening, disc spring end and connected with the external ruler, to pull the disc spring tightening (some of the tightening force of disc spring before the ruler did not pull out), not to pull the disc spring with a ruler to relax, recover. Want to know the structure, remove a box ruler, understand everything.
The internal structure of a wheel shaft, the outer winding ruler. Rule around the wheel axle can rotate but his center by the spring pulling when you pull the foot wheel will be with the rotation this spring is also a time when you were suspended. The release this spring will pull the wheel back. Then the ruler would follow.
