WW1 Fuze N°83 II, what are the small screw and spring in the fixed ring for?

[WestFront]

Hello,

In attachment, you can find the pictures of a WW1 fuze N°83 II.
In the fixed ring, there is a small screw, see the red arrows in the pictures.
Under this small screw there is a small spring situated also. In the right picture, you can see these two parts separated from the fixed ring, and in size compared with the time detonator unit.

I wonder what are these two parts for?

The only thing I can imagine, is that under the small spring there should be a steel needle (disappeared by corrosion?), that touches the time safety pin. As soon the time safety pin is withdrawn, the needle is pushed down by the small spring, and blocks the entrance of the time safety pin. It is unable now to put back the time safety pin (done for safety reasons?).

Who can help me with detailed drawings and/or explanation of these two components?

Greetings,

WestFront

 

[Alpini]

Two features come to my mind:

1. the spring + a small plug were closing the safety pin hole to ensure that the ignition flame was going the right way to ignite the powder train and not leaking outside through the safety pin hole.
2. during flight no air (pressure) could enter through the safety pin hole which could disturb the smooth/constant burning time of the powder in the rings (better precision)

The Treatise on Ammunition, 1915 Ed. shows this part of the No.81 fuze (same construction) but doesn't describe the "why":

 

[WestFront]

Thanks for your quick replay! Indeed, the 'Treatise on Ammunition' gives more detailed drawings. Your explanation makes sense! Now I can look for the remainders of the 'Closing pellet'. Its name tells us already that it is used to close the safety pin hole!