The mounting of spiral springs is very simple. The springs are not usually pretensioned and are fixed in most cases
with just a pin or bolt.
A special criterion here is the position of the inner end in relation to the outer end, as this influences the angle of twist and therefore has a direct impact on the torque.
For the position of the ends in relation to each other, a tolerance range of +/- 20 degrees is standard for automatic series production. The mechanism assigned to the spiral spring should be at zero at the start of work. This difference must be taken into account and should ideally be readjusted.
Because their relatively large coil spacing makes spiral springs easy to support, the design of the shape of the outer end
can be kept simple.
The length of the angled hook depends on the cross-section. The bending radius should be at least twice the thickness of the material.
If critical bends are required at the outer end, the material must be soft annealed before it is shaped in order to prevent cracks and fractures.
The inner coil of a spiral spring does not necessarily have to be in positive contact with the shaft, which allows for simple designs of the shape of the inner end. It is important to note at this point that if the degree of bending is high, the end of the spring must be soft annealed beforehand and the length of the hook must be of a size sufficient for the outer hook.
There are many possible designs of the inner end. The choice of inner end shape should however always depend on its functionality and efficient production processes.
