Finger ring provided with an adapter device for automatically adjusting the ring size

1. A ring defining a seat for being worn on a finger and comprising:

a structure; and

an adapter device for automatically adjusting the diameter of the seat, the adapter device comprising:

a) at least three arms, equally spaced along an internal periphery of the structure, each one of the arms coupled to said structure so as to rotate between a retracted position and a forward position with respect to the center of said seat; and

b) elastic means radially interposed between said structure and each arm to push each arm to the forward position; said elastic means comprising a plurality of parallel and spaced elongated elastic elements,

wherein each elongated elastic element has a profile substantially extending in a circumferential direction and comprises a wire spring, each wire spring comprising:

a first end portion having an end fixed to one of said structure and a respective one of said at least three arms at a welding zone; and

a second end portion, opposite to said first end portion along said circumferential direction and arranged resting against the other of said structure and said respective one of said at least three arms.

2. The ring according to claim 1 , wherein said end of each first end portion is fixed by means of laser welding.

3. The ring according to claim 1 , wherein said end of each first end portion is fixed to said respective one of said at least three arms.

4. The ring according to claim 3 , wherein said first end portion is defined by a substantially rectilinear portion, tangential to said respective one of said at least three arms and engaging a passage which is fixed with respect to said respective one of said at least three arms.

5. The ring according to claim 4 , wherein the size of said substantially rectilinear portion is approximately the size of said passage, to insert said end into said passage during the assembly.

6. The ring according to claim 5 , wherein said passage is defined by a rear surface of said respective one of said at least three arms and a semi-cylindrical portion fixed to said rear surface.

7. The ring according to claim 3 , wherein said respective one of said at least three arms has a U-shaped cross section and defines a rear compartment accommodating said end.

8. The ring according to claim 3 , wherein said end of each first end portion is fixed at said welding zone to a hinging bushing of said respective one of said at least three arms.

9. The ring according to claim 3 , wherein said second end portion is arched with a concavity facing towards said respective one of said at least three arms.

10. The ring according to claim 1 , wherein said structure defines an internal channel, which accommodates said elastic means and communicates with said seat through a window engaged by said respective one of said at least three arms.

11. The ring according to claim 1 , wherein each arm includes a pivotally mounted end and a free end, and further comprising a protrusion extending from proximate to the free end of each arm and a shoulder extending from the structure, wherein the protrusion is positioned radially outward from the shoulder, and wherein when each arm rotates from the retracted position to the forward position, the forward position of each arm is determined by the position at which each respective protrusion is blocked by each respective shoulder.